will a stock 454 Throttle body fit on a 91 Camaro with a TBI 305 that has a stock intake manifold

 

technically yes. actually nope. the stock intake has smaller bores then the 454 TB

 

Get yourself a spare manifold (junkyard or swap meet) and have the bores opened to 2". A decent machine shop should do it. Then you can bolt it on, may have to splice a few wires if the new tbi doesn't have the same tps and iac hookups

but be forewarned if you have a stock engine, this will not do a thing but flood it. it will run fine until you romp on it, at which point the 305 will drown in exxon and you won't go anywhere.

been there, done that.

 

You gotta watch though that the factory TBI intake has water jackets running around the plenum. It's actually kinda difficult to open up the 1 11/16" bores to 2" without hitting a water jacket. A better route would be a 4bbl manifold with a TBI to carb adaptor.

 

good point. i got lucky with both of mine.

 

Oh yeah you can get lucky and miss the water jackets but it's difficult to do.