I just bout a new 1986 camaro z28 305 carbed. I love this car!!! But i want to make it faster!! Is it really worth putting money into the 305 or should i swap it??? I don't need anything crazy fast i just want to get from 0 to 60 a little faster!! Thanx

 

I have a TPI 305 in my GTA. They arent very fast stock, but some little mods make a big diff. The person who owned the car before put in a 3:73 rear end. Thats a big difference. Changing the shifting points in the tranny is also a large noticable difference. A vette servo will also help the shifting automatic.

 

cam and some head work on those stock heads will do wonders for 305's

get a comp cams 2032 cam, or someting close to it (430ish lift, 210ish for duration)

step two, new timing chain

step 3, get the heads redone- new valve job (this alone will help), spend about 200 bucks on porting for the exhuast ports, have the pushrod slots lengthened for the higher lift, and some decent, not crazy valve springs put on...

step4, headers and cat back

step 5, junk that quadrabog and get a holley or soemthing, and a vac. adv distib...

ste6 6, put it togther, and have fun running mid to high 13's

 

How fast do you want to go? The 305 will only take you so far. Do you have a 1/4 goal?

 

Or aftermarket heads. 1.94" intake valves a big plus regardless.

That's a roller cam. '86 would be flat tappet. Mine would work.

That's normally assumed with a new cam, but yes, a good idea along with sprockets. Double roller better than stock-type.

Valve job also assumed with porting, certainly with larger valves. The porting can be done at home (although the valve job is best left to a shop). Slot lengthening only required with 1.6 rockers. Springs to match the cam, make sure you have adequate guide-to-retainer clearance for the cam, positive valve stem seals a good way to get right sealing and clearance. Seriously consider screw-in rocker studs, or pin the press-ins of stock heads.

Agreed. And 3" high-flow cat.

Absolute waste of money. Upgrade the coil and module, tune the carb secondaries. Spend your money where it will make a difference. If you will only be racing this thing, a Holley DP carb can be justified, but if you're only racing it, why are you keeping the 305?

Not with a stock converter or air cleaner. Higher stall, traction mods required, dual-snorkel air cleaner lets it breathe, works better overall than an open element.

About $2500 later, you'll have a good-running car.

 

I really don't want anything crazy!! I just want something to beat a few r!cers!! I like the idea of the rear and i wanted 2 put a trans go with a tranny cooler in it!! I also want a new cam and a full exhaust. I already have a edlbrock performer intake.. Replace the coil and would that make it half way decent?

 

The weaknesses of that motor are: Single-snorkel air cleaner; exhaust; cam; stock stall speed converter; ignition; heads; gears. In that order. Somewhere in there you need to make sure the carb is properly tuned, including the AV opening (there's a tech article on this board about that). Notice I didn't mention intake manifold. You have to modify at least all of the things I just mentioned before you need to consider an aftermarket intake, and the Performer isn't the right one to consider then (no better than stock).

 

they make a flat tappet version of the 2032 cam... the biggest reason to do the timing chain/etc woud be the ceramic cam gear. besides the point the better chain is a plus

as for the heads, i ran press in studs. Lengthening the pushrod holes is necesary if you run more than 430 lift, and is not dependant on 1.6 rockers, altho, those would also requier lengthing the holes as well. this was 1.84/1.50 LG4 heads i was running btw.


agreed, carb not a must, but i never had any luck with a qjet...


Traction mods? what are you talking about? i had none what so ever.

i dynoed with stock heads, rebuilt with a valve job, not even any porting, a performer intake, 1 5/8 headers, 3" cat back @ 235rwhp and 272rwtrq....

the car ran mid 13.8@ 103 w/ a 2.0 60' on street tires (formula wheels)

cost was WAYYYYY under 1000 bucks...

steve

 

Take Five7's advice here... he knows what he is talking about better than just about anyone else here at TGO.

(No offence intended to anyone here)

 

If hes using an auto with a reasonable stall he probably will. I cant even come close to being able to have traction in first regardless of the speed im going with the stock high torque multiplication TC if i step on the gas all of a sudden. Even though it might not be necessary at a properly prepped track traction mods will certanly help on the street.

 

When I got my 86z It was pretty much a 350lg4 lol, it was a 350 shortblock and everything else was bolted on from the previous lg4. That being the case it had the q-jet, single snorkel etc. First things I did to the car were get an open element, tune the q-jet and get a flamethrower coil. Just that along with a tune made a HUUUGE difference. Then I did headers, cutout and flowcrapper catback, that made a nice difference as well. It was amazing at what just letting the engine breath would do. Then I got greedy and tore the motor apart, but thats another story lol. Anyways, I know it wasn't a 305 but my point is that you have to get that thing to breath, have you looked at the exh. system on an lg4? Its horrible, tiny and crimped to death, I don't think my daily driver sentra with a 1.6l could breath efficiently through that lol.

edit: oh yea and the q-jet with an open element is awesome, when those massive secondaries open :hail: ...I don't know why the qjet gets such a bad rep, I think people are scared of it.

 

A used TPI 350 would be a night and day difference over that engine. If you got another car, some dough, some motivation, and know a couple of knowledgable car guys who can help, pull that 305 out. You'd have to get a new wiring harness and ecm, which would be a pain to install, but there's tons of help to be had here if you ever go through w/ a swap. Don't mess around w/ the 305 though, unless you just can't afford a swap. But like said if you have limited funds, the 305 can still scoot w/ the right mods. I've learned one thing over the last few year, which is kinda of cliche, but save up and do things right once. At least set a goal for your car that you know you'll be happy w/ a couple yrs down the road. Most likely you'll want to continue your quest for hp later on, but hopefully it'll be awhile.

 

That's what I was saying. He would need a flat-tappet version, such as the 2050 I have.

You can keep the costs down if you are willing to sacrifice emissions-legality (which I can't), and longevity. We've all seen magazine articles where they make awesome dyno numbers modifying stock engines on this little budget; what we typically forget is their end-of-article note about how the #6 rod came out the side of the block, or it started puking oil after the 2nd pull, or the broken ring lands when they investigated the sudden loss of power, etc.

 

i would suggest starting with EXTERNAL boltons, and chassis/ drivetrain mods. once you get that stuff done, and you think your as far as you can go then i would put together a mild 350 with vortec heads or maybe basic AFR's if you have the money. A good 350 can be built for about 2000 bucks. In my opinion going through all the trouble and expense of swapping cams and porting heads isn't worth it when for a little more money and time you can get a 350 with good heads and even a roller cam if you find the right core.

 

i ran all the external mods on my 305 car, and quite honestly, i barely pulled a 14.8....

my car was 5 speed, not an autobtw, and it had a posi 342 rear in it.

anyways, i never saw any big diff in perfromance (besides yanking the stock exhaust off) until i put on the rebuilt heads and the cam... even that stuff with the stock manifolds and cat back would make a big difference..

food for thought!

 

I agree with you, i just think it makes sense to do what you can while getting ready for the new motor. ultimately a fresh 350 is a better choice, because of the increased potential of the motor and the fact that its a new motor, which most 3rd gens are usually about ready for. Its amazing how cheap you can build a healthy 350 for. I think its safe to say its quicker to drop in a new 350 than swap heads and a cam, its not too much more money either.

 

If you don't do the "external" things - exhaust, air cleaner - a 350 will not make any more power than the 305 for the same money. Remember, we're talking an LG4 here.

I agree that a cam will make more difference than the externals alone. But, without the externals, the cam will have the same problem as the 350 above.

 

agreed

 

my thoughts behind doing a swap like the cam first is that you will get some added performance right off the bat, and then even greater from the bolt on external mods

agreed tho, if you can swing the cash and have the shop to do the swap in, thats the way to go, even if its a more or less stock 350 with a moderate cam in it...

 

I disagree with that Tim. It is clear from dyno tests that an Edelbrock Performer intake will add about 20 hp, once the 3" exhaust and 1 5/8" headers are installed.

You can, of course, choose another intake and one is limited only by what will fit under the hood, or whether you need the exhaust crossover passage in order to warm the carb sufficiently in the winter.

But the Performer is definitely a step up from the stock intake

 

I would agree its an upgrade if the cam is done... if the cam isn't done, than i would think it might hurt bottom end power... the performe DOES flow better than the stock manifold, but will only be a benifit if the motor can take advantage of it.

 

Yeah, 5-7

Gotta disagree with that too. My Weiand plus made a difference - especially in the mid-upper RPM range...and it's smog legal!!

 

I didn't say the stock manifold was as good as the Action+ .

I do know how much difference the ZZ3 take-off (very similar to the Action+) made on a stock LG4. It wasn't 20 HP, and it's a much better manifold than the Performer. Admittedly, that was before headers.

The original proposition was to put the Performer on and expect a big increase. I'm saying (and I think you all are actually agreeing) that the other mods have to come before the intake change is needed. What I am also saying (that you might not be agreeing with) is the Performer isn't enough better to make it worthwhile. Personally, if I hadn't gotten the sweatheart deal on the GMPP manifold, I would have gasket matched and cleaned up the factory manifold and left it at that (spacer, possibly).

Let's also not forget that different 305s got different manifolds over the years. I am completely familiar with the '86 style that is part of the engine the originator wants to improve. It's not the factory's worst effort by a long shot.

Anywho, there are smart mods to do on an LG4, and expensive not-so-smart mods. As one member has shown, you can get pretty good results with minimal money if you are smart. $600-$700 replacing the carb, manifold & distributor is not a smart start, especially if that's all you do (and so many people seem to think the carb is the first thing they need to replace with something aftermarket).

 

Ok im gunna ask this question and I know im gunna get the two answers that made me ask the question, but I want it from people who have experiance in it.



Is the 1.94 valve too big and will it be shrouded by the 305's small bore? I had a very extensive chat with SLP IROC and he posted pics and all this saying that it would be shrouded. I asked why World puts the 1.94 valve in to there 305 Torquer heads. Now, I am still not convinced that the 1.94 will be shrouded as I have never heard of anyone with teh World heads having any problem with the vavles hitting the deck of the block. I really want to have the 1.94 vavles installed. Please someone with experiance give me a strait answer.

 

OK bigal,

I've ported and polished my own 305 heads (601 castings) and had 1.94" intake valves installed. It works fine. Other folks on here have done it to their 416 and 081 castings just as successfully.

Here is what you do; lay the head gasket on top of the head and then trace the outline of the cylinder opening onto it with a pencil. Then use your die grinder to open up the outside of the combustion chamber around the intake valve, all the while staying within the circle.

Job done

Follow the link at the end of my sig for a complete how-to including pics

 

Here's a pic of how they look. Notice the unshrounding. The machine shop did the final touches for free. Nice guys.

Here is another tip. Notice how I champfered the edges of the combustion chamber? You can do this easily by taking a little piece of regular old sandpaper and rubbing the edges with you thumb. Doesn't take long at all and guarantees you won't get any preignition from sharp lingering edges creating a hot spot.

By the way, 1.94" valves should be worth an extra 10 hp or so above 4000 rpm, so you are making a smart move

 

He must be smoking some good stuff. I've mocked up a bare block with TFS 23* heads (2.02/1.60 that apparently dont fit on a 305) and valve shrouding probably would not occur until about .540-.570 as estimated with a few camshaft profiles. I've never mocked up a block with 1.94 to test it because I am very certain that there is absolutely no problem with 1.94's and 305s.

 

Thanks guys, and thanks sitting bull. I have an extra set of 081 heads I am going to go get milled and decked, but Im going to attemt to port the heads myself.