Has anyone built a stroked LG4? Aside from the usual "building a 350 is cheaper" line, are there downsides to the build (cylinder walls too thin, heads too weak/anemic, etc)? Any tips?

 

other than spending more money and putting way more effort into it for less preformance than a 350 it's a wonderful idea.

 

You tell me what's more satisfying, a 14 second 350 TPI Z28 that everyone tries to mess with on the street and you're expected to be a challenge, or a 14 second Sport Coupe that looks like it does 18s with a V6 and looks completely stock under the hood?

Well... I'd take the Z28, too, but I still think it's a cool idea. So seriously, are there any particular weaknesses in the LG4 that I would have to worry about? Or has anyone done this?

 

Tunedport335 did it with.... a tuned port motor, aside from the induction, it'd be the same thing...

But as discussed before, the cost of a 350 block is negligable compared to the power increase... and no one can tell a 305-350 block from outward appearance, just keep the sport coupe exterior...

 

How about a 14-sec (at sea level, anyway) Berlinetta that looks completely stock exterior and under the hood, and passes strict emissions inspection and testing?

The primary weakness of the LG4 is the small bore that shrouds the valves. The stroker kit doesn't do anything to change that. Getting an extra 100 HP out of an LG4 doesn't require any shortblock disassembly or machine work, or the $700+ to increase the stroke.

It's all about the amount of air you move in and out of the cylinders, and that's done with a combination of induction, efficient head ports, proper cam selection, proper exhaust handling, displacement, and RPMs. It will cost you more just to get the 335 rotating assembly and required accessories than it would to get and rebuild a 350 shortblock, and you still need to machine and clearance the 305 block to put in the 335 kit - and you'll end up with 20 cubes less than the rebuilt 350.

It didn't make sense 4 years ago when I looked into it, and it still doesn't make sense today.

(BTW, LG4's have large journal cranks. )

 

Yup...and he ran a 13.4 or something with 2.73 gears...

 

as long as you know going in you'll spend more to get less and aren't fooling yourself at what the results will be go for it. not like i never built a 266 engine for more that a 350 would of cost, even pulled a 350 out to drop the little engine in.

 

Yeah ede, I'm aware it will cost plenty. I think there's something unique and interesting about a sport coupe with it's original block and original trans pushing 14s (maybe 13s as mentioned above?). I plan on keeping the emissions and A/C too (so much for 13s).

I've had ideas before and I never went through with them. It's just another one of mine, so who knows what will happen. I still need to pick up a daily driver if I plan on doing this.

 

Makes just as much sense as boring and stroking a 350 to a 383 instead of buying a 400 block and building a 406!!!!


I don't see why it is a bad idea personally. The 335 will make just as much torque (maybe more)than a 350. It has to do with the extra 1/4" of stroke. The 1/4" of stroke is usually worth about 30 ft/lbs neglecting the displacement increase. Lets say a mild naturally aspirated 305 makes 350 ft/lbs of torque. That 1.1475 ft/lbs a cubic inch. Now multiply that by 334 that makes 383.2 based on the displacement increas. Now add the 30 ft/lbs from the increased stroke. on top of that. That comes to 413 ft/lbs. Makes perfect sense to me.


I have seen a 335 on the dyno with L31 350 vortec heads, 9.5:1 compression, edelbrock vortec spreadbore intake, stock untuned 1984 truck Q-jet, stock LG4 cam, stock 1984 C10 truck HEI distributer and headers on it churn out 410 ft/lbs @ 2,000 rpm and make 276 HP @ 4,500. Up the cam to pull to 5,300 or so and see where I am going. This engine is in a 1984 C10 pickup and man will it run. Engine now has 30,000 miles or so on it. (I will try to find the dynosheets for the non-believers)

Oh and as far as the small bore being a problem I think it was Hot Rod that just did an article where the built up two big blocks with the same displacement. One had a bigger bore and shorter stroke and the other a smaller bore and a longer stroke. The one with the longer stroke handed the large bore motor its rear all the way to like 5,000 rpm where the larger bore inched ahead. Guess which one I would choose for a street motor. The longer stroke. You also have to consider what these guys are able to get out of their import motors naturally aspirated. Most have a bore that is smaller than 3.5". My moms Acura V6 3.2L has a 3.54" bore and a 3.310" stroke yet makes 230 net hp showroom stock. Granted it is OHC and has 4 tiny valves per cylinder, it is still making well over 1.15 net hp per cube with a tiny bore. It further amazes me that it is done in a luxury car with a dead smooth idle at 550 rpm and passes emissions very easily.

 

Where does this "extra torque" supposedly come from?

This is a great example of flawed reasoning. I won't bother you with the formal Latin name for it; it basically translates to "circular reasoning".

Torque is proportional to 3 things: cyl pressure, piston area, stroke.

Piston area time stroke is the definition of "displacement".... cubic inches. This is not affected by the bore-to-stroke ratio. In other words, x number of inches is x number of inches, no matter whether those inches come from bore or stroke.

Cyl pressure is a function of how much you manage to raise the temperature of the gas in the cyl by burning it. Again, the bore-to-stroke ratio does not affect cyl fill; except in the case of the 3.766 x 3.75 motor compared to say 4.030 x 3.25 (a .030" over 327, which is almost exactly the same number of inches), you have the NEGATIVE effect of poor cyl fill caused by bore shrouding. Not a "positive" effect at all.

Therefore, a 334 CID engine will make less torque than a 350 CID motor, all else about the motors being equal.

So simple you can outsmart yourself on it.

 

The increased torque comes from increased leverage on the crank. You have a displacement increase which increases the Compression ratio (which increases cylinder pressure) as well as increased leverage from the stroke being longer.

Also your cylinder pressure is going to spike quicker (less distance for the flame front to travel) on a smaller bore engine which means that the power stroke can be started later and there is less negative work done on the piston as the air/fuel mixture burns (reasoning behind fast burn chambers and swirl ports)

I also hate to mention it but on a street engine at any reasonable RPM valve shrouding doesn't really effect the power of a 350 or a 305 in that matter. Oh boy you lost 5 whole horsepower to a shrouded bore. Take a flow bench and try the same head with a 3.75" bore simulator and a 4.00 inch one. It will flow almost the same, trust me I have tried it on a "193", "081", and "601". They were all within 4-5 cfm even with the smaller bore.

You are also forgetting important things with friction, combusion characteristics of the smaller bore, TDC piston dwell, rod to crank angles, etc.

 

We already eliminated that source of possible confusion and misdirection. We're comparing "otherwise equal" motors.You have increased leverage, with the longer stroke; but you also have decreased force on the top of the piston. PSI times piston area.

In other words, if you have a given number of cubic inches, and the engine is producing a given amount of torque; and you them rebuild the motor such that it has twice the stroke and half the bore, you end up with half the force pushing the piston down, and twice the leverage, for a net change of exactly ZERO. If you do the opposite thing and halve the stroke and double the bore, thus keeping the CID the same again, you end up with twice the pounds and half the leverage, again producing a net change of zero.

That's what's wrong with that reasoning.

Brore shrouding can be a considerable source of poor cyl fill at higher RPMs; not so much of an issue at lower RPMs of course.

There's no difference in "flame travel". However many cc's of air/fuel is going to burn however fast, regardless of whether the piston moved a long way or a short way to compress it there.

There's no way that the change in "friction" is going to produce this imaginary 10% increase in torque you're imagining. That's just WRONG, period.

 

Yeah but you are increasing the stroke and keeping the bore the same.

I have seen a 350 on the dyno with no changes other than a set of 400 rods and a stroker crank pickup 70 ft/lbs. That was a stock 350 with just a crank and rod change.

 

No, I'm not...

Inch per inch, torque remains the same; regardless of whether those inches came from bore or stroke. You don't get extra torque depending on the engine dimensions, if the displacement is held constant. The RPM at which it occurs might vary slightly, but torque remains the same. This crap you put up about a 335 having 30 ft-lbs more torque than a 350 is typical of why people make wrong decisions. Garbage in, garbage out.

And of course a 383 makes more torque than a 350. It should. It had better. It's more inches!!

You also don't get more torque out of one brand of cast iron than another. The gasoline molecules release the same energy, no matter what company molded the container they're in. So lets' not go down that road either.

 

I agree with Five-7 Kid.... It's not the shortblock... it's the cyl heads and the rest of the motor.

5 liters is NOT a small motor. And to be completely honest, the short blocks of most motors have NOT changed at all.. most motors however are build now to produce a bit more horsepower in the top end, and therefore they beef up the bottom end to handle the extra RPMs... like 4-bolt mains.

But if you want more power, you'll have to go with some aftermarket cyl heads and a new camshaft. Your camshaft is the FIRST big restriction. As soon as you get a good came, you'll realise that your cyl heads are the next big restriction.

In my opinion, if the rest of your motor is stock... I personally would first get rid of the computer control (if you still have it). Computers are wonderful for modern cars, even the older cars that have TPI and MPFI.. they're great... even TBI... but a computer has no business on a carburetor.

I would do the follwing in this order (assuming everything else is stock:

1 - Get rid of the carburetor, get yourself a good vacuum advance MSD Distributor.

2 - Replace your carburetor with a nicely rebuilt NON CC Rochester Quadrjet (600 cfm), or an Edelbrock Carburetor.

3 - Replace your stock intake with something that matches up to whatever carb you chose.. a 3701 or whatver.

4 - I recommend keeping your EGR system as it does help cool your pistons.

5 - Open element K&N air cleaner. (or just a K&N air filter if you've got the dual snorkle or cowl-induction)

6 - Get yourself a good set of headers. If you have emissions testing, then get a set of TES Edelbrock, or a set of FlowTech headers with the matched Y-pipe.

7 - REPLACE your old stock catalytic converters with new ones (if you haven't already done so). Those old brick cats are horrible... as a matter of fact, an OEM cat from any newer car will flow better than those old charcoal cats.

8 - Replace your ignition coil with a high output one... (might already have one if your msd distributor came with one).

9 - Give your motor a GOOD chemical cleaning like BG Chemical cleaner, or seafoam.

10 - Replace your fuel filter, your oil filter, and switch to half-synthetic. (unless you're already comfortable using full synethetic).

11 - Replace your spark plugs with steel tipped AC Delco.. none of that pansy platinum tipped stuff.

12 - Get yourself a good set of 8mm plug wires.


Everything else on the motor still stock... you should be running at the very least... low 15s in the quarter.

I did this to my 82 TransAm when I used to have it...

The reason why I say to spend the money on all these other items is... because should you decide that you still want even MORE power.. you can always re-use ALL of that stuff you just bought... with a new 350 crate, or new cyl heads. So you're still gaining power, and not wasting your money. What WOULD be a crying shame... is to spend all that money on a crate motor, and hook it up with all ghetto old parts...

Unless you have tons of money and it's not an issue... but if that's the case, you probably wouldn't be asking us.?

If you're still not satisfied, then get yourself a DECENT Crane Cam... nothing too radical, but something that has a better lift and duration than your stock cam (actually... almost anything is an improvement over the LG4 Peanut cam). If you STILL want more power, but don't want to go through the hassle of replacing the cam, then you can install a set of roller rockers. You can go with a set of 1.6:1 roller tipped rocker arms and that'll almost be like replacing your cam.. you'll get more lift, etc.

Even if you DO replace your cam, I still recommend getting roller rockers. Me personally, I would rather get a decent cam, and install a set of 1.52:1 roller rockers than a mild cam with 1.6s... but that's just me.


By this point, you should be running high 14s in the quarter... anyone that says otherwise either hasn't done it themselves, or their car is loaded down.

By the way, I'm assuming you at least have a decent gear ratio... if you still have a 2.73:1 Unlimited Slip differential.. you'll want to go with something a bit more aggressive.

In my opinion, I'd suggest going with a 3.08:1 LSD. That will STILL give you improved acceleration, improved traction, and you won't notice a bit of difference in fuel economy. Actually, with those other mods I mentioned, you can expect to pick up 2-3 miles to the gallon in the city, and probably close to 4 on the highway.


Anyway, if you STILL want more power... then you have to swap out the cyl heads.... and if you're going to swap out the cyl heads... you'll probably want to rebuild the bottom end... with the added compression... it won't be very good for your rings.

Let me know if you need any additional info.. I did all this stuff to my 82 TransAm back in the day.

 

Like RB is trying to explain to everyone, cubic inch is cubic inch. You will make the same amount of power no matter how you get that cubic inch, as long as they're the same.

Say you have a 305CI motor that makes 500HP. That's approximately 1.64HP/Cubic Inch

Then you take that whole top end and cam and such off, and put it on a 335. Since you know that the top end makes 1.64HP/Cubic Inch, you'll know that 1.64 x 335 = 549HP

That's a 49 HP gain by putting on 30 more cubic inches... GREAT! Right?

Well, we wouldnt make that much on a 350 now would we? Because the smaller bore and longer stroke of the 335 makes it rev high right? Well, lets do the math

1.64 x 350 = 574.

Thus, a gain of 74HP from the 305... incase you arent getting the trend of this, I'll leave you with some numbers.

1.64 x 383 = 628
1.64 x 400 = 656



To CaysE... you wanted to know how much a 335 LG4 would make? Well, I believe the "best" stock one made for our cars put out 165HP with the 305.

That's about .54HP/Cubic Inch. (165/305 for anyone wanting the exact numbers).

so .54 x 335 = 180

You will gain 15 horses with about 1600 into your motor to turn it into one of those high revving, torque monsters that they call a 335.

Or, you can do the math for a 350, .54 x 350 = 189, and gain 9 more horsepower than a 335, and save yourself about 1000 dollars.

 

Too bad those 2.02/1.60 heads won't fit on a 335

nor most good aftermarket heads.

CaysE, if I had to do my motor over again, it would look the same, sound the same, but displace another 51 ci. I read an article awhile ago where some crazy a*holes built a large 400+ based stroker in a TPI car, put in a grandpa cam, and the thing idled and sounded stock...until you hit it. Plenty of ways to go stealth and sound stock. Big ci, great heads, and the grandpa cam. Solid low 12 second sleeper!!

 

You're on a bit of a high horse.... and you seem to respond with a bit of arrogance, but that's cool... as long as things end up the way he wants them, then that's great.


However, my suggestion to him is to simply upgrade everything else first. Anything that he buys in the way of upgrades, he can always re-use. I think you'll see it's kind of hard to find a flaw with that.

NOT doing those things first would be wasteful... there's nothing more lame than having an awesome motor, and then bolting cast iron LG4 exhaust manifolds onto it with AIR Injection.


As for the computer... computer control on carbureted motors are horrible. I'm not scared of computers, nor am I carburetor ****. I have written my own ALDL software and have OBD-1 scan tools that I use on my Fieros. I've also reflashed the ECMs in both my 97 Grand Am GT and my 2002 Crown Vic.

However, the computer system used in the LG4 computers is practically one of the oldest forms of OBD-1. It barely qualifies as OBD-1... if it didn't have on board diagnostics management, it would be no different than the ESC found in the 1980/1981 301 Pontiac Firebirds.

The bus on those computers run at 300 baud, and actaully.. a multiple spark discharge distributor with mechanical or vacuum advance would be significantly better than going with a stock GM HEI distributor and OBD-1 computer control.

If he had TPI, or even TBI, I would agree with you.

I'm not sure if you realize this, but the OBD-1 computer was installed to control the emissions equipment... it's completely unlike the OBD-1 computers found in the MPFI and TPI cars.


And, EGR systems do cool the piston tops. EGR has nothing to do with AIR injection, I don't know how you can say that EGR introduces air into the engine? That's the AIR Injection system. EGR is Exhaust Gas Recirculation... it recycles exhaust gasses by re-introducing them into the intake. It ONLY does this under certain conditions, when the motor has reached a certain temperature (which is typically handled by a thermostatically controlled valve in the intake's coolant stream on NON CC cars), or when the car is in closed loop mode.

At wide open throttle, the EGR system closes and the car gets only fresh air.

And another thing, there's no way that a 305 could possibly need 700+ CFM.

I have a 350 4-bolt, a CMJ block, nickle re-inforced, with HO Corvette heads. 2.02:1 intake and 1.6:1 exhuast. I have a 600 CFM carburetor on that motor... if 600 cfm is plenty for the 350 in my 81 TransAm, it's more than enough on a 305.


AS for the K&N air filter.... a 305 LG4 motor is hardly a technological marvel that a piece of dust would wreck havoc on it's rings. A K&N air filter is an ideal perfect filter to use on a car that's carbureted.

The ONLY reason why someone MIGHT want to stay clear of a K&N air filter is if they have a fuel injection system that utilizes a MASS AIR FLOW system... in which case the oil and dust might coat the filament in the MAF sensor.

His carbureted motor doesn't have that issue.... sand cannot penetrate a K&N air filter any easier than it does a paper filter.


Anyway.... why not just offer your OWN advice rather than trying to disprove everyone else's?

 

I'd offer advice, but CaysE was not even asking how to upgrade a motor. He's a moderator after all. All he wanted to know was if someone had stroked a LG4 into a 335. I'm assuming his reasoning was for more power (isnt that what everyone's after here? ).

Thus, I told him how much to expect from a 335 LG4.

I didnt mean to insult you, I was trying to keep misinformation from spreading... it's just like those people who say "yeah, you cant have that 3" exhaust, you need backpressure for the exhaust to work right" that spread misinformation around.

As for EGR, I still dont see where you proved that recirculating exhaust gasses will cool the pistons? Nor did I see where it was stated that cold pistons are a good thing? The whole setup of an engine is made to run optimally at a certain temperature. Metal expands and contracts via temperature, so it would only make sense that making the pistons colder would reduce efficiency...

In short... keep EGR, it's good for idle quality.. that's the short n sweet version of it

As for the computer, I am very intrigued about how the system works exactly. You seem to have fiddled with it enough, and since you said the ECM on our cars are nothing but garbage, what aftermarket ECM might you suggest?

Getting rid of the computer system would be fine for a carb setup, except when emissions time rolls around. And I will be making several moves from state to state pretty soon, and will need to go through emissions several times... so if you can suggest a aftermarket computer system for the CCC QuadraJet please say so.

I'm only meaning this as a friendly arguement, I dont intend to insult you.

 

Nah, it's cool... I was just slightly annoyed by how you took each item line by line and disagreed with basically everything. I've been wrong PLENTY of times, and if I'm wrong in any of this, it certainly wouldn't be the first time.

I am by no means an expert, but I have done all of these things to engines that I've owned, and based on the research that I've done, and my experience (as limited or as extensive as it may be) these tend to make significant differences...


I'll discuss two items, the EGR system and the ECM.

The EGR system DOES actually cool the motor. I don't fully understand the scientific reasoning... but this is what I pulled from the first web site that was returned to me on a brief search:

"EGR system
The EGR system (Exhaust Gas Recirculation system) is designed to reduce emissions. To be precise, it lowers the amount of nitrogen oxide (NO) in the exhaust emissions. Nitrogen oxide is formed at very high combustion temperatures. What the EGR system actually does is direct part of the exhaust gases back into the intake manifold, which in turn helps reduce the combustion temperature and consequently lower the amount of NO in the exhaust gases. The EGR flow is controlled by the engine computer which opens or closes the EGR valve depending on the operating conditions. One of the most common problems related to EGR is the intake passage or the EGR valve getting clogged with carbon deposits causing restrictions to the EGR gas flow. This turns the "check engine" light on and sets the code PO401 - insufficient EGR flow (this is a common problem for the Acura / Honda V6 engine, for example). This problem happens mostly if a car makes only short trips so it can't warm up fully, or when the oil is not changed regularly. "

I found that at: http://www.samarins.com/glossary/#egr

However, they are not 100% correct... early computer controlled cars (like the 80/81 TransAm, and late 70s Cadillacs, the EGR was still managed by a thermostatically controlled valve. This valve was basically installed in the intake manifold. It would have a bypass which would disengage the EGR system at WOT.

All cars have this now.. when you floor it, the computer (or in the case of non computer control, a vacuum solenoid) would disengage the EGR system and give the motor everything it needs. (No exhaust recirculation).

When the driver is not pounding the crap out of his car, the EGR system will re-engage (under normal driving) and cool the pistons by recirculating the exhaust gasses (as described above).

This is why it's always recommended for people to keep the EGR system installed on their cars... as EGR doesn't hurt the performance of your car at all when you're flooring it. I'd also recommend that he go with a 180 degree thermostat (I forgot to mention that). I don't recommend going with anything lower than that though.


As far as the computer goes... the ECM used on the carbureted cars is VERY old technology. It worked very well at the time, but honestly, all that it really provides is computer controlled spark timing. a GOOD replacement distributor with multiple spark discharge technology (not to be confused specifically with the MSD brand) will outperform anything that a 1st generation OBD-1 computer is capable of. There were many revisions of the OBD-1 computer, including the later ones which were pre-OBD-2. The ones used on the carburetors are the 1st generation... hardly a step up, if any... from the earliest ESC computers.

Holley and Edelbrock do offer computer management systems... but my own personal recommendation is to just ditch the computer. Unless you are in a state that requires a visual inspection of all the smog and emissions equipment, you don't really have to worry. If you follow all the steps I listed above, with an msd distributor and high output ignition coil, and a GOOD set of free-flow catalytic converters, and you KEEP the EGR system and the Fuel EVAP system... you will pass emissions with flying colors... with improved mileage, and improved emissions than any OBD-1 CCC vehicle could be capable of.

They offer mechanical advance distributors, or vacuum advance distributors. There is a very slight delay that's inherent with vacuum advance, but all the gains that are made up with the replacement parts far outweigh the initial lag with the vacuum advance.

If you still want computer control and better timing management, you can go with an MSD boxm like a 6A or 6AL... they even offer them now with knock sensor control.

A knock sensor really isn't that helpful for a basic V8 motor unless you're using forced induction, or you have heavy carbon building. In the case of carbon buildup, you would want a professional cleaning through the use of Seafoam or BG-44 Chemical Cleaner kit... (Which works wonders by the way...).

CCC doesn't really improve all weather starting or anything anyway... the computer controlled carbureted vehicles still use the antiquated THERMAC system... which is basically where... you have a thermostatically controlled valve (often the same one that the EGR runs off of). When the motor is stone cold... it closes a flap which redirects the intake of the air from the air cleaner. Instead of getting it from the fresh air duct at the front of the hood, it'll take the air from an aluminum "dryer hose" which connects to a coupler attached to a series of aluminum heat shields which are bolted to one of the exhaust manifolds (usually the drivers side manifold). It basically sucks air past the outside of the manifolds to help warm up the car.

In almost every car that I've seen, this system is totally inoperable... the dryer hose is usually removed, or the heat shields are missing....

The ONLY benefit that a stock CCC has on a stock motor is helping to advance timing when the car is floored based on the information it gets from the TPS.

But the bit stream of those ECMs are so friggin slow, that pretty much anything you replace it with now will be 100x better.

When you really start to modify your motor... the computer ends up becoming a hinderance....

Like for example, if you go with a high output cam.. one that say... lowers the manifold vacuum pressure... this upsets the MAP sensor... often times you have to end up switching to a different MAP sensor because it's expecting to see the vacuum at a certain level... if it doesn't see that, then it starts switching to fuel maps in the computer that are not optimal for the operation of the vehicle.

Basically, as soon as you do any kind of noticable modifications to your motor... the ECM starts to become a hinderance. Unless you have the capability to burn a new chip... you're better off just ditching the entire system anyway.

Take for example, something as simple as a catalytic converter.. Back in the early 80s, the factory catalytic converters did what they were supposed to... but they were absolutely horrible. They were basically steel canisters filled with charcoal pellets (not unlike the fuel evap canister) and you were expected to force exhuast gasses through that.... they were extremely restrictive.

Some of the hugest gains possible in the early 3rd gens is swapping to aftermarket catalytic converters. Hell... the STOCK catalytic converters on my 1997 Grand Am GT are less restrictive than the stock cats on an early 3rd gen.

The technology of distributors and carburetors have continued to improve, while the stock ECM remains what it was in 1982 when it was given OBD-1 control.

 

On a side note... there are actually replacements for the stock OBD-1 computer for the MPFI and TPI systems that will GREATLY improve the performance of an otherwise totally stock computer / engine combination.

OBD-2 RISC systems are much more advanced than OBD-1. Although cars come from the factory (in almost every situation) usually very conservatively tuned, you can get some ridiculous power increases by the most modest of computer tunes. Computers now are much more efficient than they were, and with the improved bus speed... the computers are able to make much faster calculations than before. At 300 baud... you can almost tell the computer what the sensor numeric values are faster than it can read them through the bus!

 

I think you're assuming that the top end would remain the same, which it definitely wouldn't. I would like to keep the stock heads, but they'd have to be ported at least, and the intake manifold would be changed. I have a Holley rebuilt Q-jet that would stay with it, including all the emissions, the computer, accessories... everything. NJ has strict emissions testing and they test visual. This won't be the fastest thirdgen by far, but it's my idea of what Chevy could have done in 86 with this motor while remaining street legal. 160hp out of a 305ci is mind boggling to me, I'm sure this number could be put into the high 200s with 30 more inches, head work, exhaust, better ignition and a good tune while keeping the smog and accesories, with 300hp+/300ftlbs+ being the ultimate goal.
While I won't be doing this with a 350 block to push 401ci, you're on exactly the same page I am.
LOL... are you suggesting that my moderator status means that I know how to build a motor? Cause I moderate the Appearance, Vendor Review, and Northeast forums. I can detail a car fairly well, and I know the thirdgen suspension and interior fairly well, and I can rip on or commend a vendor with the best of them, but I have never torn down an engine myself. I've helped with a couple rebuilds on Fords, but that's about it. I'm just doing a lot of reading and brewing up ideas, really. Feel free to offer all the advice you wish.

As far as the rest of this idea goes, it would have headers with AIR (probably SLP), cat with AIR (haven't decided which), and a well-flowing cat-back with the typical 1-in 2-out muffler with turn downs tucked behind the bumper, stainless steel, no idea on which. The ignition would be the stock distributor (probably needs a little work) with an HO coil, upgraded module if I can find one, 8mm wires and always the Delco plugs. If there is a way to make the stock computer faster like one of the TPI or MPFI upgrades I'd like to do that. Cooling system will remain stock as I don't think I need anything better than what's on the car. I replaced the radiator recently and put in a 180 stat and the fan hardly ever comes on unless in traffic. If I can somehow make a single snorkel air cleaner flow more air from somewhere I'd do that too, but I have a dual snorkel I can put on.

 

Ok, so you have to maintain all your emissions because of a visual inspection?

Well, if I were in your shoes, THIS is what I would personally do (starting off with these mods):

1 - Tune up your car, new plugs, new wires, switch to synethetic. If you see any leaks, fix them. I use synthetic in all my cars, and they don't leak. You shouldn't have leaks. If you do, you have to fix them... there's no point in upgrading a motor if it leaks oil. Correcting the oil leaks should be your primary concern.

2 - New fuel filter, K&N air filter, a good Purolator Microfilter or an AC Delco Microfilter.

3 - Get yourself a GOOD decarbonizer kit. I mean a GOOD kit... BG-44 Chemical cleaner (3-stage kit), or seafoam. I can't express enough how important this is.

4 - Replace your exhaust manifolds and Y-pipe with a set of headers and matched Y-pipe. I don't really see the need of going with SLP headers... they are very expensive and they don't deliver THAT much greater advantage over a set of TES Edelbrock headers. You can get the TES Edelbrock with Air Injection and an 02 Bung. If you want to save a bit more money, you can also go with a GOOD set of FlowTech headers (you can order them with AIR fittings and 02 bung also). If you can afford SLP.. then you can probably afford a complete 350 swap.

5 - Replace your catalytic converter or converters with a set of HIGH-FLOW cats. You can keep your muffler stock, or switch to a Flowmaster. But from this point... you won't really see much improvement.

6 - Get yourself a dual snorkle air cleaner. OR... if you can find one... get yourself a cowl induction hood. THe ones for the LG4 will bolt right up to your motor... make sure it's not for the CFI or it won't fit. You'll see a definite increase in power on the highway. If you're really broke, and can't afford a dual snorkle... you can upgrade your single snorkle air cleaner by hacking up another one and taking that snorkle and riveting it to your old air cleaner. (thereby making two).

7 - Upgrade your 02 sensor to a newer AC Delco O2 sensor... the newer O2 sensors are much more reliable and efficient.

8 - Upgrade your MAP sensor with a brand new AC Delco one. The original MAP sensors have a much more limited range of reading... often times, when the manifold pressure drops a little (like at idle or something) the MAP sensor passes control over completely to the IAT and TPS sensors... thereby often causing a hunting idle (not to be confused with a gooked up IAC sensor valve). Anyway, the replacement MAP sensors from GM are MUCH more efficient and can offer a much greater range of reading to the ECM than the original older MAP sensors. MOST aftermarket MAP sensors however are designed to the specifications of the original MAP sensor. So make sure you get an AC Delco one.

9 - Spray the HELL out of your throttle body with carb cleaner.

10 - Replace your Intake manifold with an Edelbrock Performer 3701 EGR intake manifold. 100% street legal, more efficient, and better cooling.

11 - Replace your ignition coil with a HIGH OUTPUT coil from Accel or MSD.

12 - Install a 180 degree thermostat.

At this point you should see some SERIOUS horsepower gains. I'd expect that... starting with 160hp (what year do you have?).. you're likely to see about 180-185 horsepower. You'll also have much more torque, the motor will be more responsive, and you'll have much improved fuel economy.


If you still want more power than that, there are some other things you can do:


12 - Replace your distributor with an aftermarket MSD or Accel multiple spark discharge distributor (can be used with factory computer). This will allow you to gap your plugs a little bit higher.

13 - Install a set of underdrive pulleys, and a replacement higher output alternator. You'll get less drag on the rotating assembly which will equate to quicker revs.

14 - If you want to keep your stock cam, but improve HP, you can switch to a set of 1.6:1 roller rockers. You can expect a very decent improvement in horsepower from these... (around 8-10 horsepower with the 1.6s). (this will also reduce drag on the rotating assembly)

You'll probably have about 190hp from these modifications (I'm being conservative so you may even have more).


If you still want MORE horsepower, then you'll have to start tearing into the motor:

1 - Remove the cyl heads and have them ported and polished. (or you can do it yourself). (and a decent valve job)

2 - Depending on how many miles you have on the stock motor, you can deck the heads SLIGHTLY (matched with the intake) and that'll boost compression (which will give you a nice HP increase). Only do this if you intend to rebuild the bottom end.

3 - Replace your cam with an aftermarket one. Edelbrock offers a decent one called the Performer cam 2102.

4 - While you're down there, replace your timing gears with a set of Cloyes true-roller gears.

5 - Port-match everything before you put it back together.

6 - Replace your rear gears with at least a 3.08:1 or a 3.23:1 and LSD. Despite what's been said, higher gears DO actually in fact improve your acceleration substantially.. if this wasn't the case, drag racers would all be using 2.73:1 rear gears.


At this point, I don't see why you wouldn't have ~220 horsepower or more. You should be running mid 14s no problem. You may want a shift kit to firm up the shifts too.

The nice thing about this is... should you feel the need to go to a 350, you can re-use everything you just bought (cept the timing gears and the camshaft).

 

Woo hoo!! 220 hp. Gol-ley gomer, woo hoo!! 12 years ago my raggedy-a$$ 305HO went 14.10 @ 98mph with almost no oil pressure on a 150K mile motor, with a couple of idiots installing "ancient" parts.

Rebuild your stock motor, port your stock heads, and be sure and get pistons that will give you 9.5:1 compression. Use a good set of 1 5/8" headers and 3" exhaust.

Get the quadrajet redone, and run the zz4 intake. Comp cams 218/224 xe cam blah blah blah, and a good trans and 3.73 gears. You can run faster than I did without knowing how to drive.

Blah blah blah, blah blah blah, it's only money!!

BTW, 12 years ago, this combo was very quick on the street. Now, I don't know, you might run into a WRX and still get your a$$ kicked!! Good luck and post whatever you decide to do.

 

Damn, I almost wish that I had a stock LG4 3rd gen again... just so that I could see what I could get out of it with a stock 305 block and heads. It would make an interesting writeup... but then again... the 3rd gen is getting so old now, that it's not often people find an original one with low enough miles that it's worth upgrading without rebuilding... :\

 

Not exactly, but I plan to keep everything in there anyway. If it becomes a serious problem, it can be removed afterwards.

1 - Already changed the plugs and wires, and plan to keep it up to maintenance schedules. I'm not going to switch to synthetic before I rebuild the motor. If anything it will be afterward.

2 - Already has a new fuel filter and K&N

3 - I'll give the Seafoam a try.

4 - I'll compare the headers you mentioned to the SLP. Please let me reiterate, money is not the issue here; I'm trying to attain a project goal which does not include "maximum hp" or "lowest budget," but does include reliability. I haven't read anything bad about the SLP coating yet. Correct me if I'm wrong.

5 - I'll definitely put on a high-flow cat if it's as reliable as an OEM.

6 - Already have a dual snorkel, and a cowl hood is not going on this car.

7 - Good advice.

8 - More good advice.

9 - Carb is new as of a couple thousand miles ago. I do clean it once in a while with carb cleaner.

10 - I'll definitely take this in consideration as well as the ZZ4 intake.

11 - Already have one.

12 - Already have one.

Unfortunately, I'm not seeing many HP gains because the engine is so tired. The valvetrain is weak and the compression is low in a couple cylinders. When I do this build (or if), the block is going to be freshened up and everything else is going to be fixed and/or replaced from the ground up.


12 - Would a complete replacement distributor be a big improvement over a coil/module/cap/rotor replacement?

13 - Already have a 140amp alt, but underdrive pulleys aren't going on the car either. I will try to get lighter pulleys however, and try to either rebuild or replace the accessories so as to rotate more freely.

14 - I wouldn't mind switching to roller rockers, but if I do that I'll end up working on the whole valve train, which means the heads will come off, which means I'll want to get the heads ported, which means I'll wait until I can do the whole engine.

190hp sounds good, but it just won't happen with the condition my engine is in right now. A rebuild is all that's really going to help it at the moment. Maybe if someone has another LG4 that works good and will sell to me I can swap that in and do the work on the original engine in the meantime.

1 - This will be done when the engine is rebuilt.

2 - More stuff when the engine is rebuilt.

3 - I'll check out that cam.

4 - Good idea, I'll look into that too.

5 - Naturally.

6 - I plan to go with a 3.23 or 3.42 LSD rear with disk brakes, which will probably happen before the engine gets done.

The trans is going to be rebuilt as well with a shift kit, and it definitely needs it. Thanks for your insight.

 

There's one in my buddy's backyard, pasadena MD. It's free. Will need to be redone. Right next to it is an 86 Monte SS L69 motor. It's free too. It will need to be redone also. Let's see what you can do!! PM me and you can pick them both up!!

 

Well, it depends on what you get, just replacing it with a new one, you should notice a big improvement in idle, response, and power... that's assuming yours is original. Specifically what wears out is the pickup coil. These can be replaced quite easily, but you have to dissasemble the distributor (have to knock out the pin and pull the shaft out). If you do decide to spend the money on a replacement distributor.. check out MSD's site... you can go with something like this: http://www.msdignition.com/dist_5.htm
Send them an e-mail... they'll tell you what's the best distributor for your application.


Just so you know, you don't have to do anything special to install roller rockers. You simply unbolt the old rocker arms, and bolt this in place. You don't have to dissasemble anything but remove the valve covers. You'll have to set the valve lash, but that's not hard to do at ALL.. it explains it in the Haynes or Chilton's repair manual.


Honestly, if I were you, and I had your motor... I would probably just stick some 1.6:1 roller rockers in there...


You'll see 8-10 hp increase with the 1.6s.