ok lets get some input thinking of pulling my 305 outta my 91 camaro and installing a flat tappet 350 but i want to keep my tbi will the 305 heads work decent enough on the 350 what intake should i run and what computer do i need to change to its what else do i need to do what cam should i use?
tia for any ideas

 

by the way it is a 5 speed car and want to keep the ac and cruise but want to have occasional track trips

 

I bought the 350 H.O. crate motor for my 92 RS (a flat tappet cam motor, intended for carbs) and with my current setup, I am NOT impressed and I know the TBI is killing me. I have spent a little over 3 grand on my new setup and I'm still in the 17's I bet, but I'm still using critical 305 parts that I know aren't letting me unleash the power of this motor (Torque converter,stock 2.73 gears and 305 injectors). If you do a swap with TBI, just do not expect to do it for cheap and not a lot of work to get your car to run with even 3800 Motors (low 15's to high 14's).

If you do the motor swap and KEEP TBI, here are some things I WISH I would have waited to do:

1)Bore out the GMPP Vortec TBI manifold out to two inch bores to accomidate a projection TBI base or 454 TBI base and installed a 454 TBI base.

2)Order a 350 Chip from TBIchips.com FIRST. It barely ran right with the Jet Stage 2 305 TBI chip I had in there. After I put the 350 prom in, it immediately drove better and got rid of hesitation but it sill didn't break the tires loose like it should've.

3)Get the Vacuum FPR from GM for like 89 bucks, I still plan on purchasing this. The APFRs run WAY to rich at normal cruising speeds or idle (flood at start unless you floor it to clear the gas out) but still run lean at WOT. Hence the Vacuum one, a guy that has a 91 RS did this, I forget his site but I know he likes Syracuse University and has a Grand Prix GT for a daily...If you read this, please chime in.


I do not care what the other members say about the stock fuel pump, if you KEEP the stock TBI on a 350, IT WILL GIVE YOU ENOUGH GAS! TBI supplies PLENTY of fuel, just not nearly enough air flow. Before you other members that HAVE done this swap and say wait till the bottom of my post.

I'm running an Ultimate TBI, 1" cfm-tech tbi spacer, and injector spacer on my 350 H.O. crate motor and with the JET APFR turned ALL the way down and I cut the first coil off the spring, it still RUNS EXTREMELY rich and blows carbon out of the tail pipes and would stall out at lights because of it flooding. And this is with 44lb/hr 305 injectors!

I ordered a set of 350 cop injectors (65lb/hr) and I'm going to run them with my stock FPR and see what happens, hopefully make the car run a LOT faster because right now, my car runs like a lightly modded 305 TBI should, I'll explain that later.

For the members that HAVE put a 350 on a TBI equipped F-body, that are going to say to what I have said, this is ALL from my PERSONAL experience. I have only WOT my new motor 3-4 times because I know at WOT I'm running lean, no way in hell are stock 305 injectors and FPR going to supply me enough gas at WOT on a 350 H.O. motor. Supplies plenty of gas for normal driving though.

To explain the 350 h.o. runs like a 305 TBI thing, my g/f and I were on the way to work and we lined up and I got the 3-4 car jump on her, then when I started getting near 70, I heard that 3800 scream and she blew my doors off and she got like 3 car links on me and I shut down at 80. She had to be in the 90-95mph range...What car does she drive? 2001 Pontiac Grand Prix GT with a K&N drop in as the ONLY mod.

If you go on this excursion, know you have a LOT of work ahead of you, a lot of tuning and buy at least 3.42 gears to compliment. Since you have 5 speed, you don't have to worry about the higher stall TQ converter.

Good luck.

P.S. I've been told many times the 305 TBI heads were the WORST heads EVER made by GM. Might want to get different heads..

 

Yeah hes right , it takes alot of work to make the swap from 305-350 work on tbi cars, I did the swap on my car and wasnt impressed , once I mixed and matched the right parts ,and played with it a little I was very pleased. First you want to run a chip out of a 350 tbi truck ,second you want a holley 670 cfm throttle body,it comes with the injectors you need and an adjustable fuel regulator. You do not want to keep the 305 heads they are restrictive as hell.If your going to get a 350 get a long block, if your worried about the tbi manifold not working w/ the old style heads get a carb manifold and put a tbi adapter plate on it . You can get one from www.turbocity.com.You want to ditch as much as you possibly can from the 305 setup. When i first put my full roller 350 in I had headers and exhaust and I was running high 15's ,then all i did was change the chip and injectors ,and adjust the fuel pressure and I was breaking 14's.Also you can use the stock pump but after modifying the engine a little you want a better one.Other people may tell you to do different ,but this is how it worked out for me , it takes some time and some thought ,and alot of hard work to get it to perform the way you want it to but its well worth it in the end . Good luck man.

 

thanx for the info so far keep it coming