Epro

Has anyone made these engines perform?

Stekman

They can be made to perform however you want them to. Namely, for whatever amount you dump into it.

I had an LG4 in my Caprice a year ago:
Ported 416 heads
Comp xe256h cam
ZZ4 intake
Edelbrock 600 cfm carb
Mallory HEI ignition

The thing ran fine for me. Good guts for an LG4 that was a daily driver. In your case, though, if the carb and ignition are still working, probably in your best interest to keep them as they optimize fuel economy.

sofakingdom

iTrader: (1)

No, no one. Ever.

Seriously...

The choke points in that setup are, in the order they should be fixed:

1. Exhaust
2. Cam
3. Air cleaner
4. Electric fan
5. Gears
6. Heads
7. Converter (if it's an auto)

Notice that at NO POINT did I mention the carb, intake, or ignition system; hacking off any emissions eqpt; aftermarket "chips"; add-on ignition boxes; or other typical wastes of money. The reason those are wastes of money, is that THEY ARE NOT THE THINGS LIMITING THE CAR'S PERFORMANCE. Note also that I said "car", not "engine"; as not all of the things that make those slow, are under the hood.

1. Exhaust - needs to be replaced, as an entire unit. Every piece from the heads to the back bumper. The replacement MUST NOT be designed to fit LG4; because if it is, it will PRESERVE the LG4 exhaust bottleneck, namely, the itty bitty Y-pipe. Get one of the quality brands of headers SPECIFICALLY for one of these cars, BUT NOT for the LG4; get the ones for a TPI 350. Get a high-flow cat such as a Catco from Summit, and your choice of cat-back. All of this for something like 89 TPI 350 without G92 (single-cat setup). This will retain emissions legality (except for the EFE valve).

2. Look at cams in the 210 - 215 degree @ .050" range on the intake, with a larger exhaust lobe. Comp's XE256 and XE262 are known to work well. Crane has cams of somewhat similar specs that also give good results; I think it's the Energizer 272 but I could be wrong. Lunati's new Voodoo series is the right design for this, and may have something in the right duration range for it. Whatever cam you pick, avoid choosing it based on "sound"; any cam that "sounds" "good" will probably be too much for the rest of the engine and car. Replace the valve springs and their hardware, and the timing set, along with the cam. DO NOT try to use a modern cam under stock springs; you'll probably break something.

3. Get a dual-snorkel one from L69. This will give several HP over a typical open element, since it will give the motor cold (dense) air instead of hot, thin underhood air.

4. If your car has a clutch fan, it uses a good solid 12 HP just to run the fan. An electric fan will give you back those HP. Watch the classifieds on this site for a used fan setup.

5. Those cars were always the "sacrificial lambs" to CAFE in the V8 F-body product lineup. At the time they were new, the people who bought them were looking for the "image", not the "substance", of performance. Since anybody that was buying a new car and was seriously interested in performance avoided those like the plague, I guess GM figured they could nut them as much as they wanted to get their fuel mileage up, and nobody that bought them would care (might even like them better in fact, if they were cheaper to drive; no matter how slow). So they always got crappy gears. The best they ever got, standard, was 3.23; and most years they got 2.73 or the like. 3.42 or 3.73 makes an AMAZING difference to a 2.73 car. If yours already has 3.23s, it's not quite so urgent; but once you get the motor to breathe, it will benefit from 3.73s. In stock condition though, 3.73s will force the engine RPM so quickly up into a range where the motor has no power, that it won't really be any faster than stock; even though it will feel like it has this huge launch off the line.

6. The heads themselves are fine, entirely adequate for 305; except that they can use some porting, and larger intake valves. There is a great deal of HP available here.

7. This is like gears. The stock converter pins the motor to a very low RPM range, especially from a stop. Once you get it to where the motor has some higher-RPM power, letting it rev up when you punch it will give it a much harder "leave".


I cannot emphasize enough, RESIST THE TEMPTATION to un-bolt and re-bolt big shiny things that sit up there where everybody can see them, on top of the motor. There's an old saying you'll hear at the race track, from the people who WIN: "Chrome don't bring the money home". People who spend their limited cash on "dress-up" are choosing the path to a slow expensive car that loses races.

The parts that produce performance are INVISIBLE. Don't let that discourage you from doing the right thing. Spending your money on things you can "see", will produce little or no results; except maybe, the car will be lighter, because the driver's wallet will be thinner.

Which reminds me of another whole set of things you can do to make the CAR faster; and that is, lose weight. I don't advise hacking stuff off; few things make me puke as bad as all the people who hack off their AC, for example. But, any time you replace something, make an effort to get something lighter in its place. For example, a "mini-starter", a plastic/aluminum radiator instead of copper/brass, an aluminum drive shaft, lighter wheels, lighter flywheel if it's a 5-speed, aluminum bumper support to replace the steel one, the 82-83 "composite" hood, etc. etc. etc. You can shave an easy hundred pounds off of it that way, maybe more.

naf

iTrader: (7)

Sofakingdom has some good advice, although I'm not sure if he writes it up on the spur of the moment or does the cut/paste from a library of pre-written advice.

sofakingdom

iTrader: (1)

Good idea!! Maybe I should do that, keep from making my fingers so tired.

Fast355

iTrader: (2)

I will add some info to sofakingdom's advice.

A.) If you decide to port the heads, I would pick up a pair of 601s from the wrecking yard. They are like mini 462s in the chamber, have better flowing ports than the 416s stock, and have a 52 cc chamber. That will bring the otherwise stock LG4 from 8.6:1 compression to about 9.2:1. This will add compression and flow, which will increase HP.

B.)The CCQ-Jet is VERY adaptable by changing out mechanical parts and settings. The limiters on the mixture control solenoid can be adjusted to put out the correct air/fuel ratio on the primaries. There are many different primary jet/metering rod combinations from the general. Some cars came with big jets/big rods(V8 4bbls) and some cars cam with smaller jets and smaller rods(V6 2bbl such as the 3.8). Dual Jet metering rods and jets will swap to a Q-Jet. Combine the bigger jets with the smaller rods and viola, more fuel flow on the primaries. Don't worry though as you can set the limiters. The secondary metering rods and jets can be tailored to provide the best WOT power.

C.)If you could find a L-69 chip, they are best for performance and could actually increase the fuel mileage some. Short of a L69 ECM or chip, you might find that boosting the base timing to between 4-6* will add performance and MPG.

five7kid

iTrader: (14)

The '85 & '86 LG4's had 4-relief flat top pistons, bringing compression up to 9.5:1. '87 has slight dish pistons that dropped it back down to 9.3:1. On those engines, 52cc chambers may raise compression too much.

'86 & '87 had the electric radiator fan.

I never had mine on the dyno, but from dragstrip performance it calculated out to around 250 RWHP at sea level. Not bad for a stock bottom end.

Did anyone mention not bothering to rebuild a stock bottom end?

85cmroz28

Here's a good thread for getting some performance out of the 305

https://www.thirdgen.org/techbb2/sho...hreadid=333467

five7kid

iTrader: (14)

There is this one, too https://www.thirdgen.org/techbb2/sho...hreadid=261488 .

In FAQ, no less . . .

Fast355

iTrader: (2)

I run 4-relief flat top pistons(-6 cc total), 55 cc chambers(angle milled and CCd 081s), .010 deck height, and a .029 nominal compressed gasket. That is 10.3:1, it runs fine on 93 octane gas with 32* total advance. I am injected however and have a cam that has a fair amount of overlap.

Epro

Exhaust:

Would this product fix the exhaust problem?

http://www.slponline.com/view_product.asp?P=31007

Or would it be necessary to add headers?

(Note: Edited by Moderator to eliminate the long quote, that wasn't even referenced in the next question. Guys, there's no need to "quote" just to reply!)

sofakingdom

iTrader: (1)

Yes, that exhaust would be an excellent choice; in conjunction with their 30000C headers, the 30018 "install kit", the 30038 cat adapter, and a 3" slip-fit cat such as this one here. Or, if you think you might ever change to a 350, which would need the larger primary tubes, get headers 30001C instead; all other parts the same.

A cat-back won't do too much to fix the restrictive cast-iron manifolds with undersized outlet ports, or the Y-pipe that's not much bigger than a garden hose. In fact, it's questionable whether the cat-back by itself, would make any noticeable difference at all, by itself; since those bottlenecks in front of it would still be there.

Epro

Thanks for the info, I just learned a lot from reading that!

But for all the time/money spent on an LG4, wouldn't it be smarter to just drop one of these in?

http://www.jegs.com/webapp/wcs/store...0763&langId=-1

It comes with headers. Would everything from an LG4 just bolt right in? Because that sounds a little too good to be true

Fast355

iTrader: (2)

It does NOT come with headers!!!! A 350 would be a great start, if you wanted the added expense.

sofakingdom

iTrader: (1)

No that doesn't come with headers.

That's the crappy phone-company-van replacement motor. They might call it "260 HP", and it might actually make somewhere near that, with a big intake and Holley carb and open headers and no accessories; but it made 165 HP when it was installed in cars in the 70s. Yes, the EXACT SAME MOTOR, part number for part number. You got your 993 heads, your 929 cam, your 8.2:1 compression, all right there in a crate, instead of in a 74 Impala. Still the same thing though. Which means, it'll probably make about 165 HP in one of these cars, too.

The L69, or the better TPI 305s, will run circles around that thing.

Yes it can be made better. Yes a magazine did a write-up on it, and eventually got it up to 370 HP or something, with some Vortec heads and a different cam. But by the time you do that (buy a whole motor, take it apart and throw half the parts away, and then buy more parts to replace the ones you threw away), it's not "economically attractive" any more. That is, you can get A WHOLE LOT MORE POWER, for the same or less money, some other way.

And of course, it doesn't address ANY of the problems with the CAR: gears, converter, exhaust, air cleaner. Even if you buy that motor, you still need to change the cam just like you need to change the LG4 cam, and then do all those other EXACT SAME THINGS that you would have to do to the LG4. In other words, it's not some kind of a shortcut to upgrading a LG4 CAR, that replaces doing all those other things.

naf

iTrader: (7)

There are long block crate options that are attractive if your current LG4 is tired and high on miles. The 350 HO and ZZ4 come to mind. You can use your current intake, distributor and accessories. With the addition of headers/exhaust you'd have a crate combination "around" 300 hp. You may still want to upgrade the rear-end and tranny.

My camaro has a vortec headed 350 a "mild" performance cam, headers, 2200 stall, transgo shift kit and 3.27 nine bolt. It's fun, but would get tiresome driving it every day. I drive the LG4 trans am to work every day (65 mile round trip). It's a comfortable cruise and averages 23 mpg (mixed). I plan to one day open the exhaust, install an electric fan (mainly for aesthetics) and CAI, but I'll probably leave the 2.73 (original 3.08 died and was replaced) rear end and trans/converter alone-these things will affect mpg and driveability. All depends what you're looking for.

Epro

It says it comes with headers

It produces 260hp and 350 ft/lbs of torque with a 4bbl carb and headers.

Thanks for the info though

I'm not sure if I have that kind of money though. I seen how much those headers were going to cost! Any place to get them cheaper? I really can't justify the cost of those headers...

Epro

http://www.thunderracing.com/catalog...&vid=6&pcid=52


Which the $150 one do any good?

I'm sorry, I'm still trying to learn...

Epro

http://www.hawksthirdgenparts.com/in...l?v=1&pid=9387

naf

iTrader: (7)

Try Jeg's, Summit or Scoggins-Dickey. Headers and y-pipe can be had from 250-350 and cat back (w/cat) for around the same.

If you want to go the cheap route you can find some 305/350 TPI logs and y-pipe at a j-yard and hook up an inexpensive cat and cat-back to it. The logs won't get you in tire screaming territory but it's a definite improvement over existing and practically a give away at the yards. Worth the install effort? Let me know.

naf

iTrader: (7)

Missed your earlier reply. Either of those headers will do but you'll have to add a y-pipe (around another $100).

Epro

Hey,

for an air cleaner, would this work?

http://www.hawksthirdgenparts.com/inc/sdetail/2007

Or is there a difference between an air filter and an air cleaner?

Epro

http://www.thunderracing.com/catalog...&vid=6&pcid=51

Which cam?

sofakingdom

iTrader: (1)

It also doesn't say anything about including either the 4-bbl carb OR the headers; they're not in the text, and they're not in the pic. One can assume that it requires gasoline and spark plugs as well, to produce 260 HP; but you gotta buy those extra too.

I'd advise against cheep headers. You'll hate them for every minute you own them. Save up and get good ones.

About the cheepest ones that you would not hate forever, would be the Edelbrock TES. They actually FIT the car (no small matter) as opposed to simply being associated with the car; they fit the stock exhaust, no "custom" work required; and can be bought ceramic coated. Look at the same 350 TPI application for the headers.

Other mfrs of cat-back exhausts may also cost less; but you also won't get stainless steel like the SLP, except from Borla. Edelbrock, Hooker, Slowmaster, Dynomax, etc.

The coating, by the way, is definitely worth every penny. You'll spend that much in replacing other parts under the hood that get scorched by the heat, without it. It will make you money over the long term.

Those cams are all roller cams, which you can't use. Here's the XE256 as an example of a cam known to work well in that motor.

Epro

For Headers and Y-pipe, what about hedman?

http://store.summitracing.com/defaul...1&autoview=sku

http://store.summitracing.com/defaul...9&autoview=sku

Combined it'll cost me $350 CAD to have it shipped to my door, and that seems good

That cam is priced really well too

naf

iTrader: (7)

I've got the hedmans, coated, with muffler shop fabbed y-pipe on the camaro. The coating is nice but showing it's age after nearly two years.

Also got one of the XE 256 cams w/lifters new in the box sitting in the garage. One day I'll pull the 305 to replace a leaking rear seal and put it in. Too much of a pain otherwise and too much other stuff to do now.

naf

iTrader: (7)

Those hedders are the long tubes. You'll have to go with the shorties to match the y-pipe, or go for a kit with y included.

Sonix

iTrader: (1)

EPRO, where are you located, if I may ask?


I've got the heddman 68470's, that a guy pulled from a JY here in calgary, then sold to me for $50. That's hard to beat. (lucky sob finding them...)

how many kms on the lg4? if it's old, rings are worn (chances are...) might not be worth putting a cam in, if it burns a bunch of oil and has lousy compression... I'm doing a "budget" 350 conversion, since I have the car in it's downtime over the winter... I think that's more bang for buck in the long run, might be worth considering.

five7kid

iTrader: (14)

It says if you put a 4bbl carb and headers on it, it makes 260hp. Which is what sofakingdom tried to explain. Add a $100 cam and it'll be closer to 300hp.

The main reason LG4's (or L69's, or LB9's, or LO3's, or L98's) use oil is hardened cracked valve stem seals. Fix those, upgrade the other performance killers already mentioned, enjoy those until the 350 of one sort or another is do-able.

Damon

I have installed that "universal replacement" 350 several times in place of tired old 305s. It's like you strapped a second engine under the hood. Your intake and all accessories will bolt right on (assuming an 86-down LG-4 is your starting point). It's almost 90HP over your LG-4 but it's the torque from the extra cubes that really makes the seat-of-the-pants difference.

Still, you need a good exhaust system. The stock LG-4 stuff is a pea-shooter from the manifolds back. Your stock intake with cc-QJet will still work OK, although the intake might hold you back a LITTLE. It's the exhaust that's just gotta go.

For easy of isntallation and cost I've used Hooker 1-5/8" shortie headers (they come with a y-pipe) several times with good results. Way better than stock stuff. Again, make sure you buy the kit for a same-year L-69 305 HO motor or TPI engine to get the larger 3" y-pipe. Then a 3" high flow cat (or straight pipe if emissions are not a concern for you) and a complete 3" cat-back system (Dynomax makes a good kit for cheap that also flows real well and sounds excellent). Still, you'll require a little help from an exhaust shop to help you out with some hangers, a little welding here and there, etc. It costs about $800 to put a half decent complete exhaust on a 3rd gen using all new parts.

naf

iTrader: (7)

What he said.

Kevin84Z28

iTrader: (3)

[QUOTE]Originally posted by Fast355
[B]I will add some info to sofakingdom's advice.

A.) If you decide to port the heads, I would pick up a pair of 601s from the wrecking yard. They are like mini 462s in the chamber, have better flowing ports than the 416s stock, and have a 52 cc chamber. That will bring the otherwise stock LG4 from 8.6:1 compression to about 9.2:1. This will add compression and flow, which will increase HP.

How do you identify a set of 601 heads?

Epro

I am curious, if I get newer headers, will they bolt right onto the replacement engine?

naf

iTrader: (7)

Yes, headers that fit a 305 will fit a 350.

Exhaust is probably the first upgrade one should do. It's up to you whether to follow Sofakingdom's advice (and it's usually good) and go for the top-of-the-line headers/cat back that will last you for years or the less expensive alternative that still gets you the performance and leaves funds for more. How long will you own the car?

Fast355

iTrader: (2)

[QUOTE]Originally posted by Kevin84Z28
[B]The last 3 digits of the casting number. They will usually be sitting on a 4-barrel carbed 305 in either a Van or a Truck.

Pony Killer

I took my old lg4, had some bowl work done to the heads, and a valve job, summit 204/214 cam. performer intake, 3.42 gears, 2400 stall converter, rebuilt the carb, ck rods, G hanger, stock chip, the car would ran 14.60@ 93 mph for 2 years, got 26-28mpg on the highway. not too shabby for a beat up 305

seen many a 350 under them in the 13's and get low 20's on the highway

Fast355

iTrader: (2)

Before my TBI days on my G20, I had a radical cammed (not fendershaking but loss of some low-speed, in-town driveability)Q-Jet carbed 305 that would run 14.8s @ 95 MPH all day long. You could probably still find the write-ups somewhere on here under Fast305.

Basically it was a stock 1983 305 bottem end, heavily ported and angle milled 601s (10.4:1 compression, 225 CFM/210 CFM, .550 lift), Comp Xtreme 274 cam, Edelbrock Performer RPM spreadbore intake, Q-Jet built by me (DR rods, F hanger, .070" primary jet, .050M primary metering rod, 5 in/hg power spring, 2 turns out on the APT), GM HEI ESC distributer with 16* initial advance, 18* centrifical @ 2,800 and 15* vacuum advance (manifold) and the knock sensro was left in place and functioning, Built 700r4 with a 5,800 RPM governor from a 1993 camaro LT1 transmission and a stock G-Van 2,000 rpm stall, headers, true 2 1/2" dual exhaust. It had a 3.08 posi in the rear and P255/70/R15s. It was just coming out of 2nd at the end of the 1/4!

It would still touch 16-17 MPG, but would have failed a smog test bad due to the HCs from the large overlap.

Epro

Those Hedman headers come with a lifetime warranty

I'm young, and I have to save for school soon. So that's the main reason I want to go with cheap headers.

Nate86

I can relate with you on that one (I'm 19 and in college), but for ~$1000 you can have an exhaust that flows more than the 305 will ever need to flow, and it will probably last through a decade of abuse.

Hooker 2055s - $300
Jet-Hot coating - $300
Hooker catback (aluminized steel) - $300
Catco high flow cat - $100

Took me about two months to raise the money for all of the parts... bought them seperately with each paycheck (working 40hrs/week @ $8.00/hr or about $600/biweekly with taxes taken out--I should point out that not all of the money was spent for parts on each check, either... a lot of it went to food, insurance, gas, ect). Then I collected all the parts at one time and put them on the car as a "kit."

This is the route I took for my car, and the new exhaust hasn't disappointed me yet. Well worth the money.

88_Import_Slaye

I'm a bit late, but look at the link in my sig. Of course, as stated above, the REST of the car will need work.

I took my V6 which came with 3.42's and gutted it, dropped in an 85 LG4 after building it up and I can almost drive it after 2 years!

Edit: in the article sin the link, Lunati has a 305 kit. Might be worth looking into. 305's are getting more and more popular. Heh, maybe even five7kid will become an LG4 fan.

five7kid

iTrader: (14)

Haven't been around these parts long, have you.

88_Import_Slaye

lol, long enough to know you'd respond to that comment

MillerTime21

Does it matter what year? Is any one year better than the other?

five7kid

iTrader: (14)

Do you mean, what year L69, or what year LG4?

I've heard the '85/'86 ECMs were a little more sophisticated than the earlier, but don't know if that applies to L69s or just to LG4s. Probably both, but I don't know for sure.

MillerTime21

I ment for the L69. I just didn't know if any one year is better than the other for performance.

five7kid

iTrader: (14)

I don't have my HO 350 Camaro Conversion Kit parts list with me. I believe the later ECM's were different for both L69's and LG4's. So, you'd need the chip that goes with your type of ECM.

Again, "I think. . ."

eric17422001

All this talk about exhaust and nobody has suggested Ebay or the classifieds? I scored a set of Hooker 2460's that had never been installed from what I could see for $66. Deals are out there to be had, be patient!

five7kid

iTrader: (14)

Well, this is the "Carburetors" forum, afterall.

If you spend any time on the Exhaust forum, you'd probably have come across a comment or two of mine arguing that free 2460's are too expensive to consider.

85t/alover

how do you remove the computer controlled carb on a lg4? i know that thing has to be pointless. carbs have been running fine without computer aid for a number of years. i have an 85 ws6 t/a and absolutely love it except it gets 14 mpg and the power sucks! heeeeeellllllllppppppppp!!! please!

88_Import_Slaye

do like i did, gut th engine bay, rebuild the motor with performance parts and an edelbrock 1406 4bbl carb. I need to tune it still, but it runs great. Have not yet put it through the ringer, but will soon. Build the motor with the thoughts of adding a turbo to it in near future.

of course there are cheaper options, like a new GM Performance parts crate 350.