454 throttle body on a chevy 355

[botiejeep]

I have a few questions for you guys.
Let me start with some motor specs.
Chevy 355 10.5-1 compression. .30 over 1.5 roller rockers COMP 270H cam

I had this motor in a 72 blazer and it ran great. Dyno'd at 375 HP.
I then put it in my jeep with a factory 350 tbi. The chip was burnt for the camshaft. I ran it for about a month without any problems at all, but it didnt seem to run near as good as it did before with the carb on it. So I assumed it wasnt getting near enough fuel due to the stock throttle body.
Now I have a factory chevy 454 throttle body that I am getting ready to put on. Is there anything I will have to change besides the wiring adapter for the iac?
Thanks for all the help

[Red Chevy]

The 350 intake has a smaller bore than the 454 so u may have trouble getting a good air/fuel ratio. Also, u may also want to look into an adjustable fuel regulater to go into that throttle body to up the fuel pressure to feed that beast.

[botiejeep]

I forgot to mention that I used a factory 454 adapter in case I needed to use the 454 tbi

[COMP]

are you putting it on a aftermarket intake ?

[botiejeep]

Yes the motor is out of a 72 camaro. It has an edelbrock performer intake that used to have a q-jet on it. When I put the 350 tbi on the engine I used the factory carb-454 tbi adapter.

[Bill usn-1]

There are 2 pins that will need to swap when converting the IAC. Or find someone selling an adapter.

The regualtor can be made adjustable, no reason to buy one.
There are a couple different inj's for BBC so you will need to know which. Read the numbers on top of them.

physically it will bolt on but tuning is something different.
A lot will change but sometimes you get lucky.
I assume you don't yet log data with a laptop and you don't/can't program a chip.
The AE-accel enrichment normally will be weak. You will have a slight dead spot off idle.

as you log data...which you need to do...you may find it lean on the bottom and then rich on top, or vice-versa.

You can make a compromise by adjusting the fuel pressure.

There is also the option of bolting the injectors your running now on the BBC TB. If you think you have an air problem and not a fuel problem.

Bottom line...put it together and log data.
Get a fuel pressure gauge so you can make adjustments.
If you can't get it right...then you will need to go to moates.net and get a flash and burn and make some mods to the chip.

For specifics on the mods hit the FAQ's at the link in my sig.

[Badburn]

I put a 454 throttle body on my smallblock 400. I was able to get it tuned to near perfect my making the stock regulator adjustable and lowering the fuel pressure a couple pounds. Stock cam, and stock chip(454) on mine. Hope this helps.

[botiejeep]

Thanks for the ideas. I am considering having howell burn me a new chip as well. I will check on how to adjust the fuel pressure.

[dangofast]

Contact Brian at www.tbichips.com. He has a lot of experience with tbi related swaps and has pointed me in the right direction a few times. Plus on his sight there is a lot of info to read on tbi setups in general.