Hi everyone, i have a 91 RS, and it still has a 305 with a stock 305 intake. What i was wandering is, if you could use a TBI from a 350 and be able to swap it over to mine with no problems. Any help would be greatly apreciated, thank you!!

 

No real advantage, IIRC, only the injectors are larger, which may not run correctly with you 305 calibration.

 

what are the pounds an hour difference, between 305 and 350 Throttle body injectors???? would having an adjustible fuel pressure regulator help compinsate for the change??

 

I'm not sure of the size difference, but consider this...

A smaller injector with increased pressure, will be better than a large injector with lower pressure.

Now if you've built the engine to where it needs more fuel, the larger injectors are a good idea, but for a stock or mildly modded engine, you're probably better off with the stock injectors.

 

Do a search for 350 TBI injectors and all your questions would be answered. GM 350 injectors are suposedly #55 but from independant tests done by Turbocity and others, they come up with around ~#61. The 305 injectors were said to be only #40 but in reality they are closer to #55. The crossfire 350 injectors are the largest for the small block with a #67 rating. The big block injectors came in "80" and "90" but they too are probably slightly more than that at stock fuel pressure.
Definatly a good idea to run the GM injectors with slightly more fuel pressure. GM injectors can handle the increased fuel pressure unlike the holley projection systems. You should be able to feed just about ANY 305 with the stock injectors. If you had major head and crazy cam etc then the larger injectors would probably be a wise investment.
The difference between 350 and 305 TB bore is zero. Only the big block TBI units and some holley pieces had the larger 2" bore. The stock TB with some mild porting is plenty for an engine making ~300hp, any more and it's been agreed that the 2" unit would be a good idea.

 

so i take it that i can use my stock injectors for quite a while then huh?? I think that i am going to do that then, i appreciate everyones help and knowlege. Now my next question would be, how do i make 300 horsies come to life with my little 305 TBI motor???

 

hehehe, you need to take this to the tbi board dude. i am gunning for 300 at teh wheels with mine. i got about 225rwhp from teh stock cam. it ain';t the easiest thing in the world to do, but all th eparts tranfer right over to a 350 if you get one later so it is all good.
the nice part about tbi is that you can make some really tacky looking torque nubers pretty easily. and torque is what actually moves things(hp is just a number mathematically derived from torque, it does not really exist)

later
tim