I'm trying to find out how strong a 1990 350 TPI engine is. I know it's just bascially a 350 chevy with a TPI manifold and that they have 9.3:1 compression from the factory. How stong are the bottom ends on these motors and how much HP can they handle stock? Any info on what the rods, crank, pistons, etc are made of would be helpful.

I did a search and can't find hardley anything on them.

They are plenty strong as a base for performance build-ups. The blocks are pretty stout and the stock rods can handle most street RPM levels with no problems.
I've built and worked on mildly modified street TPI motors that are in the 350(+) HP range with mostly factory parts.

Get a copy of "How to Tune and Modify TPI Engines" (by Jason Scott/Motorbooks) for specifics on internals by year/model.
John Lingenfelters' book on "Modifying Small Block Engines" (H.P. books) is also a great source of info.

Performance Cams., Injectors, Throttle assemblies, Manifolds & Runners and other 'bolt-ons' are readily available from many suppliers.

Thanks. I'm using one as a short block; just wanted to make sure they were strong enought to handle around 400hp with stock internals. Obviously the TPI is making way for a carb.

Obviously the TPI is making way for a carb.

For some reason that wouldn't have been obvious to me... :rolleyes:

Injection is more tuneable, more linear over greater RPM range, has better driveablity and delivers greater mileage - matter-of-fact, I don't know of many High-Tech modern street or Pre-touring cars with a carb. anymore...
And, in my 'Smog-Happy' state, it would be harder to sneak it by the DMV for registration reasons if they discover the block date is a 1990 and the engine confiquration no longer "resembles" the original with a carb. system. Luckily your in a state that doesn't worry about those things - yet...