92c-car

Hey fellow f-body camaro lovers! I'd like to make my 305 faster. I know most of you agree the 305 makes a better boat anchor than an engine and it's not worth building up, "get a 350 instead and go from there" but my '92 camaro is a convertible and I've heard that the frame can't handle the torque of anything bigger than a 305. I've done a tune up on it and it helped but it's still pretty poochy. I thought maybe a set of roller rockers, different heads, air intake, etc. I have a 350 turbo transmission set aside if that would do any good. Any ideas, let me know. Thanks

AmorgetRS

iTrader: (6)

The frames can handle the torque of a 350 without an issue. In 89 they made a descent number of 350 Firebird convertibles. Either way you should get a set of Subframe connectors and a wonder bar to help stiffen things up.

A Turbo 350 won't do anything to help make your 305 faster.

The basics would be headers, y-pipe and catback. A better set of rear gears, like 3.45 or somewhere around there will wake up the car a lot. You didn't mention if you have the 305 TBI or TPI motor because that does make a difference in what will help the most.

yaj15

iTrader: (3)

No matter if the car is going to be modified or not, subframe connectors should be a mandatory option. Especially on a T-Top or drop top car.

Before you start making mods try and come up with a plan for what your goals are. Do you want a fast street car? Do you want a 100% stock car to cruise in? Do you want to do some type of racing (drag racing, auto cross, etc)

Picking a direction will help you select components so that the car will be balanced and meet your needs. What are the specs on your current engine? Is it a TPI or TBI or carb? Before you start making any mods, make sure your car is in good running condition. Fluids, ignition, suspension, etc. You have to have a solid foundation to work with before making any mods because you'll never get the full value of them otherwise.

It's easier to make power with a 350 than a 305 but, that doesn't mean that you can't make the 305 perform well. A lot of parts that will work on the 305 can also be swapped over to the 350 if you so choose at a later date. Basic boltons to the intake and exhaust system would be a good place to start.

okfoz

I have a Bone stock L98 in my 1989 Formula 350 convertible, and it is fine...

T-tops and convertible conversions, all add to weight. Believe it or not the reason why some years did not come with T-tops and a 350 had everything to do with EPA MPG ratings than the structure of the car. Anything that would add weight to the car and it would not make the magic number of 22.5 mpg would not pass the test. Prime example was in 1987, you could not get (in the US) a GTA 350 W/ T-tops, the rear shade or the subwoofer, but you could get one in Canada with all of those options...

92c-car

Thanks for your reply. I have a TBI and what I'd like to do is increase the acceleration a little. I'm trying to keep it as stock as possible incase I ever do decide to sell it and the buyer wants originality so I think bolt on's are the way to go.

92c-car

Thanks for your replies. I have a TBI and I'd like to keep it as stock as possible.

AmorgetRS

iTrader: (6)

Start with SFCs and a wonderbar (both available from Top Down Solutions, along with other vendors). You'll need the right SFCs but most are pretty clear if they fit the convertibles or not.

After that, I'd go headers, y-pipe, and catback. All bolt ons, easily to swap back if you want, and don't de-value the car (imo).

For the TBI setup this section has a ton of info:

https://www.thirdgen.org/forums/tbi/

Nothing you are doing is really convertible specific so depending on what you are thinking of doing just hit up those sub-forums to get the specific info you need.

92c-car

Thanks for the info. I'm not really sure what a catback or some of the other parts you mentioned are other than the headers. I'm kind of a weekend mechanic and don't really know a whole lot about working on cars but I'm learning as I go. Maybe you could give some info on what the parts do. I know headers increase the exhaust flow but I'm not sure about the rest. Thanks again for the info.

-=Z28=-

iTrader: (3)

A cat back exhaust is a after market exhaust much better flowing system. the reason its called cat back is thats where you unbolt your old stuff and bolt up the new stuff. there is tons of options to choose from and also different mufflers to choose depending on how loud you want the car. one pipe out the back or two also i believe.

The Y-pipe is what connects the headers together before the cat. careful here as there can be fitment issues. Im sure many people here can tell you what ones fit the best.

SFC (sub frame connectors) they either bolt or weld or both to the underside of the car. from the rear lca's and run along where all the body steel is pinched and spot welded together on the outside/underside the car, up to the front by the cross member.. here again, with your convertible Id ask around for best fitment.

Good luck on your adventures

-Dan

dmccain

iTrader: (2)

The exhaust is #1. Then a posi trac unit with 3.42 or 3.73 gears and it will wake up that L03 engine. Im still haven't tackled headers yet but I have done cat-back exhaust, posi unit/gears, shift kitin the 700r4,open air cleaner, and I can tell you it feels much better.

AmorgetRS

iTrader: (6)

Headers will help a L03 motor even more than a TPI motor. The manifolds have a 2" outlet compared to 2 1/4" on the TPI motors. If you compare the side by side that 1/4" is a shockingly large difference.

dmccain

iTrader: (2)

HMM... Help it major im sure but 1.5 seconds in the 1/4 mi? Cause that's the difference in equally geared L03 vs Lb9 STOCK cars in my experience. I would say the 205 HP LB9 Auto cars 1990-1992 was underestimated to say the least. Im betting more like 220+. A lot more than a 170HP L03. My Lg4 powerd 89 Formula with headers, exhaust, and warmer cam wasn't quite as fast as my 91 Z28 Lb9 auto. In saying that I would like to see what power exactly an L03 with headers and exhaust would have. Ive started on mine with 3in exhaust and cat-delete I just lack headers and Y-pipe.

92c-car

Thanks again for the info guys. Any estimates on how much I can expect to pay for the exhaust you've all mentioned, labor and all?

chazman

iTrader: (4)

It would have been interesting if the factory had an HO version of the L03, with 2.25" exhaust manifolds, 3" exhaust or even N10, L69 air cleaner and any commensurate changes in fuel and ignition curves to take advantage of that.

tealman92

Heres a list of what you can do to up hp.
Lt1 cam
Edlebrock intake
matched injectors
Underdrive pullies
Headers and full exhaust
Computer chip
3.42 gears
Aluminum drive shaft
1985 Z28 H.O. air filter set up
Fiberglass hood to save weight
I ran mid 14's with this in a 92 rs

dmccain

iTrader: (2)

I bet with the TPI heads or 059 Vortecs you would have run very low 14s. My stock Lb9 ran 14.7s

dmccain

iTrader: (2)

Headers and y-pipe: Hedman Shorty Headers are around $180 on bottom end with matching y-pipe around $150. Jegs has a 3 in cat back exhaust for like $259. If you cant do much of this labor it will be expensive. Around here $250 for header intall and another $150 for exhaust install so you may be looking at $1000

tealman92

are the heads you speak of for a 350?

yaj15

iTrader: (3)

I've also heard that people have had good results with a converter from an S10. Stock stall is around 1,500rpm for our cars. Is it true that the S10 converters stall is a little higher, around 2,000rpm-2,200rpm? If it is that would be a cheap upgrade as well.

GM increased the stall speed from 1,500rpm on the LG4/700r4 cars to 1,900rpm on the L69/700r4 cars for a little increased performance as well.

okfoz

I put the S-10 torque convertor in my car and it helped a ton... My TC was so low that I could not stop the car in drive... I literally had to put the car into neutral when coming up to a light. When I put the S-10 TC, it was a world of difference, the car was more drivable, if that makes sense... And I have not had any problems with it either...

I am 99% sure that it had nothing to do with it, but about a year or so after I put the TC in, I lost 3 & 4, but come to find out my transmission was a replacement and it had no performance anything, so I had it rebuilt, with a custom shift kit, and a Corvette Servo and it is even better.