ZZ383 carb vs. TBI

gtj · October 13, 2005

Dear Group,

I plan to put in the GM Performance ZZ383 crate engine. I presently have the '87-'95 TBI unit which flows approx. 420 cfm and doesn't fit on either of the recommended intake manifolds GM Part# 12496822 (single plane) or 12366573 (dual plane).

I found that XtremeFI sells a machined TBI unit bored out to 50mm which flows the recommended 750 cfm, but that still wouldn't bolt onto the above intake manifolds.

Is there a performance intake or adapter that could accomplish the TBI-GM Intake mating or should I look at a 750cfm carburetor?

Any opinions or thoughts?

Thanking You In Advance,

Glenn

TieRod · October 15, 2005

Their is a adapter to make a TBI throttle body work on a carb intake. I was going to build a 400hp engine for a TBI truck that was given to me. I even have one of the adapters I bought. But I ran into a problem. A TBI can only be modified to support 350hp without going to a Edelbrock MPI conversion. So I scraped the idea and found a complete 8.1l with wiring harness.

gtj · October 17, 2005

Dear Tierod,

You can check this out:

http://www.xtremefi.com/

50mm bored GM TBI throttle body (stock is 42mm) - for up to 450hp motors

Most all throttle linkages & connector hookup combinations available for 87-95 GM Trucks, F-body, Cars, SUVs + more

Ultimate TBI modifications + bore yield 750cfm* (stock is 420cfm)

Completely rebuilt w/ NEW throttle blades, throttle shaft bearings, hardware and more

I'd still be interested in the adapter you mentioned, if you have any additional info, please pass it along.

Thanks,

Glenn

Their is a adapter to make a TBI throttle body work on a carb intake. I was going to build a 400hp engine for a TBI truck that was given to me. I even have one of the adapters I bought. But I ran into a problem. A TBI can only be modified to support 350hp without going to a Edelbrock MPI conversion. So I scraped the idea and found a complete 8.1l with wiring harness.

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TieRod · October 17, 2005

Because of companies like xtremefi. The throttle body is not the problem, it is the lack of big enough fuel injectors.

Here try this place. Look all the way at the bottom and you will see the adapter plate. http://www.cfm-tech.com/catalog/gm_tbi_per...05_products.htm

gtj · October 18, 2005

Hi Tierod,

Thanks for the web address on the TBI adapter at CFM Tech. I called them up and they have them in stock.

Do you know if the 80lb/hr or 90 lb/hr injectors from a 454 TBI unit will fit into the TBI unit from a 350 engine?

Thanks,

Glenn

Because of companies like xtremefi. The throttle body is not the problem, it is the lack of big enough fuel injectors.

Here try this place. Look all the way at the bottom and you will see the adapter plate. http://www.cfm-tech.com/catalog/gm_tbi_per...05_products.htm

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