I just bought a 91 Camaro 'z28 that came stock with the L03 305 TPI (which smokes and needs a rebuild) with automatic trans. I plan on buying a 350ci block (or more) and building it up with high performance heads, etc and retaining TPI setup. I plan on also using this car as a daily driver and I am working with a budget since I need to pay for a new motor (and performance parts) and hopefully manual transmission too.

Which 350 w/ TPI should I buy and swap in? I was thinking of the L98 from the same year since it would make finding new wiring harnesses easier. Would the A4 that came with the L03 bolt right up to the L98? Is this a good idea, or is there a better, more cost-effective motor?

 

Which system do you have, TPI (LB9), or TBI (LO3)?

 

LB9 TPI, which is the setup i wanna use

 

You don't need a '91 L98. You need a 350 long block, and the things that were different between a '91 LB9 and a '91 L98. Those differences were injectors (22 lb vs. 19 lb), knock sensor and module, and PROM tuning.

If your car has a single cat, then it's the tiny 2-1/4" system, and upgrading to a good 3" system would be very wise. If it has dual cats, it's identical to the L98 exhaust. Headers would be a good improvement, either way.

There were slight differences in cams between the '87 to '92 L98's, but that shouldn't be an issue for you. Pick a good one, tune the PROM around it and the exhaust system you use.

 

The knock sensor is the same for all 90-92 TPI's, and the knock module is built into the computer also. He just needs the injectors and the prom.

 

Okay, keep hearing different stories with regard to the KS, glad to have that cleared up.

 

you WILL want a roller block however.

 

In order to use an L98 cam, yes. In order to get something that plays with the TPI, you don't need a roller block/cam.

 

Okay, after doing a bit of research I think I want to just try and find a used LT1 due to how much power they put out. Is this a cost-efficient/easy swap to do? Is this a recomended swap for the setup I'm going to run? I will be using performance heads in addition to intake/exhaust/ignition.

 

Also I was reading about the dual cat option - the dual cats made more horsepower right? Whats a good aftermarket dual-cat exhaust system cuz I cant seem to find any and dont really want to have it custom fabricated

 

For the LT1 swap, basically remove all of your engine and TPI equipment and put LT1 stuff in its place.

For factory systems, the dual 2-1/4" cats made about 10 HP more than the ~3" single cat. However, the single 2-1/4" cat vs. 3" or dual cats is no contest.

Edelbrock and Hedman are the only companies offering dual cat headers at this time. It wouldn't be a big deal to modify the Hooker 2055 y-pipe to mate it to factory dual cat pipes, but if you don't have dual cats currently, it would be slightly more difficult. If you currently have a single cat, seriously consider the Hookers and add a direct-fit '86-'90 TPI single cat along with a cat-back for the same application. Yes, I know you have a '91, but that system will fit the engine and chassis, so unless you have a run-in with an **** Kalifornia smog **** inspektor, you won't have any problems with that setup. That system would work on an LT1 as well, FWIW.