Alright here is the deal, i've found a 400 sbc that is just too good to pass up. This is a built engine that has never been run, with all forged internals and aftermarket heads on it. My question is will it run with the tpi off of my 350. Also what would you recomend that i do to the tpi to make it work better with this set up.

 

My friend has an '86 Iroc (stock 305) swapped to 350 (bigger injectors and chip change) and currently running a 400. He's using 24# injectors, a custom burned chip, and the Accel superram intake. The thing ran great before the intake swap, but only to 4500 RPM, now it pulls hard all the way up to 6000 RPM. The MAF sensor is still a little "funky" though.

 

Considering that a stock TPI is the limiting restriction on a 305 compared to the heads, I'd say that it will be a waste of a perfectly good motor to stick such a power-robbing intake system on it. I would strongly recommend against doing that. Consider that a 305 TPI runs out of breath at about 4800 and a 350 TPI runs out of breath at about 4500; I'd expect a 400 TPI to nose over at about 4200. Pretty pitiful.

Hmmmm..... what you should do with the TPI to make it run better.... replace it with something that actually flows. My personal choice would be an Accel ProRam, if emissions would allow it.

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"So many Mustangs, so little time..."
ICON Motorsports

 

I am doing the same project right now.I have to keep the tpi because of emissions,but who has all the money to tie up in a super ram,etc..I say port it all,runners,etc..then get bigger injectors if your not making tons of horsepower.later

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"Let's get to it,well let's do it!"