Just picked up a 91 firebird with 122,000k on it for $500. Engine runs strong. Looking to rebuild or replace it, but here in oregon we have to pass emissions test to get our tags.

So was looking at 88-90 tbi 350 engines. Will these work with my existing computer? Can you stroke it to a 383 and still use the computer carb? Of course headers and intake/cam would need to be added, polishing and porting.

I would like to stay with the stock heads, since they can cost upward of $1000 for after market units. I can port/polish them, have more time than money

What's the compustion chamber size of the 305 tbi (91) and 350 88-90. I believe both these years have roller rockers. (Do the roller rockers give you any thing in the way of horsepower) or should a person go with a earlier model 350 with diffrent heads. Since I'm intersted in stroking it, the combustion chamber size will affect the piston/rods used=compresson. I want to run off of pump gas, but premium is ok.

Anyone using the powerhouse stroker kit?

Thanks bunch of questions

 

TBI heads are terrible for anything other than a bone-stock engine. Dump 'em. 305 chambers are 58cc, 350 64cc.

Find some L98 083 castings and work them over, or get aftermarket replacements (World or Pro Topline). Otherwise, this whole project is getting off on the wrong foot.

'87-up have roller lifters, not roller rockers. Roller lifters are preferred for performance and longevity, but the cams are more expensive. '88-up also need self-aligning rockers, but Worlds don't (not sure about the Toplines).

I understand you need a 350 chip in the computer, but I'm no expert on that.

Several people have used the Powerhouse stroker kits. I don't know any personally. I did approach them a couple of years ago, were rather cold & impersonal with me. Sounds like people have had better experiences with them lately.

 

Thanks, it's interesting about the heads. Looks like the L98 engine is TPI and would require a computer upgrade to change from TBI to TPI. I think a TBI to TPI conversion is more than I want to do. If I stick with the TBI carb and don't like it I can always slip on a holly and new distributer solid state ignition, fuel pump or regulator.

Can the L98 engine be used with a standard intake and carb? That would also solve my problem.

What about V31 vortec heads (1.94/1.5) 64cc/170cc intake, they can be fitted with 2.02/1.60 valves ($450). Any other heads you might consider that can be picked up cheap at the junk yard?
V31 Info Link http://www.mortec.com/notepg3.htm

I will give the TPI upgrade some thought, but it makes my brain hurt.

FYI- I rechecked the specs and could not find a 350 that has TBI just TPI and regular 4 barrel. For some reason I thought I saw a 350 with TBI carb.

 

You don't have to change to TPI to use the heads. Many people have put a non-TBI 350 under TBI successfully. Check the TBI forum for more info.

3rd gens didn't have 350 TBI or 4bbl, but Caprices did.

Vortecs have also been done with TBI on top. You need a Vortec-specific manifold with them, though. Increases the cost above the $450 you quoted.

 

Thanks will check out the TBI forum. Here's a pic of my car in progress, just put a 86 front end and hood on it could not find a 91 around here.