I read so many different threads about these swaps. Easy, hard, worth it, expensive, not that expensive, you need this that dont need this that. So I am really confused.

I would appreciate it so much if someone could help me break it down a bit. I have a 1991 Z28 Camaro with a 305TPI G92 package (higher reve, bigger cam, exhaust). Is this going to be speed density or Mass Air Flow?

Well, obviously I want to swap to a 350 because the 305 has 183k on it and is getting tired. Its about time to retire her. I can get a complete block with heads and TBI that is a 91/92 roller rocker motor. So the only thing I wont have is the accessories.

I know I will need bigger injectors. I can use my computer, but a 350 chip custom programmed for my T-5. The accessories will bolt completely up. My TPI setup will swap right over correct? It doesn't really matter that the engine is a TBI so long as its a 350. Is there something I should worry about, look for what do I need? I know there is something I'm missing. Just seems to simple.

Edit: Are the heads going to be the same from a TBI and TPI? I know they'll work together but are they different?

 

The TBI heads are different. They are the "swirl port" heads. They have a little swirl-inducing ramp in the intake path. Good bottom end, especially with TPI.

The top end might feel weaker since the ramp gets in the way, then again the extra cubes may make it feel stronger.

 

you can use that 350 TBI roller motor, with the roller lifters, get a new roller cam that's more agressive, yet EFI friendly.
Then use your 305 heads (or buy nice aftermarket heads, depends on the budget), port them up.
Re-use all your accessories from the 305. All you'll do is swap blocks, nothing magic.

no clues about the ECM or MA/SD or nothing, i'm old school

 

Hmm, I never really though about using my heads. I heard they aren't the best but I guess they would do the trick until I could get some good heads. As far as the cam, I wanted to put a cam in it anyways because they aren't really expensive just a bitch to put in. So if I have the motor already tore down why not.

Thanks for the input

 

You have to watch using the 305 heads on the 350 as far chambers go. You dont want to be running 10.5 to 1 compression or possibly higher. Just a thought.

 

Why would u not want to run 10.5 or higher? if anything thats better... atleast thats what i've heard . Im planning on doin the same swap from my TPI 305, just pull off all the TPI stuff, stick it on my 350 TBI, but gonna P&P the 305 heads, put them on, but still dont know what i have to do for computer controls for the higher compression and extra 50 cubes.

 

High compression, low duration cam, and street driving don't go together very well.

Dished pistons and 305 heads go together okay on a 350. Most TBI 350's have dished pistons. But, you'd need to know exactly what pistons you have so you can keep streetable pump-gas compression in the 9.5:1 range.

 

man im glad you said that i was about to use my 305tbi heads on my 383 that im building. if i used a long duration cam would that be ok? i also have some 350 tbi heads off a truck engine but i here they have s shaped runners and are veary restrictive

 

TBI 305 and TBI350 heads are very similar, and not what i'd want to use in a 383. Especially if you wanted to do the good name of "383" justice.

 

trust me im not using them by choice my 305 is about to give up the ghost so if im doing a swap im going big. when i get some more cash im gonna throw a vortec setup and a good cam in for now its just gonna have to be a low powered 383. i plan on doing a mild port on the tbi heads and get rid of that swirl ramp. i hear they flow a hell of a lot better without it.

 

you can get 416's, 081's, 083's, or 113's all for $400 or less for a pair in decent shape...the first three i listed can be had for $200 or less in most cases...check those out first...they all flow far better than the 187 or 193 tbi heads.

just a break down:
416's-305 HO heads (they came on the l69 and lg4 heads...they are good heads and have a 58cc combustion chamber)
081's-stock 305 TPI heads (basically identical to the 416's but have centerbolt valve covers and 72* middle intake bolts)
083's-stock 350 TPI heads (these came on the F-body L98's and flow just a little better than the two previous heads due to the 1.94" intake valve instead of the 1.84" intake valve on the 305 heads and a 64cc combustion chamber)
113's-stock 350 TPI heads *aluminum(these heads came on the corvette l98's and flow really good with a mild bowl blend, 58cc combustion chamber.


my personal experience with the 416's were on my first 305, i went 13.03 @ 103mph with stock heads, fresh valve job and a backcut on the valves

experience with the 113's was first on a 10.2:1 350 with a solid cam, went 12.16@110mph babying it out of the whole with WAY more in her. they had a mild bowl blend and a back cut with fresh valve job. on the 305 and same basic combo minus 50 cubic inches, it's been 12.50@106.8mph with more in her.