350 to 383 ?

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Oct 5, 2007 | 09:42 PM

mkj269420

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Intermediate

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From: Clarksville Tn

350 to 383 ?

I'm taking my 350 from my 82 to build 383. Already I have the 400 crank, harmonic balancer and the flywheel. Now my question is as far as the crossfire. I'm sending the throttle bodies to the machine shop and the extrution and cutting away of the side walls on the swirl plates are complete. Is this going to be enough fuel to push a 383 or should i scrap the crossfire idea?

Oct 5, 2007 | 10:09 PM

Durango_Boy

Team Owner

Joined: Aug 2006

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From: Columbia Missouri

Quote:

Originally Posted by mkj269420

Might be hard to tune properly. I like the tunability of the single TBI throttle bodies found on a lot of the late '80s and early '90s engines. There are even after market controllers for them and they look just like a carb under the air cleaner.

You could easily tune one for a 383 from what I have seen done to them. I have no direct experience with the single throttle bodies but I have seen a lot of wild projects with them.

Oct 5, 2007 | 10:19 PM

KyleDallas

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From: Texas

The manifold is the most restrictive part of the equation... the Throttle
Bodies can be modded to work.... use the OFFY crossram with
Bored out Crossfire TB's and you'll flow enough air for a 383...

The stock Crossfire manifold was choking the stock 350.... a poor
choice, even hogged out, for a 383

Oct 5, 2007 | 10:56 PM

I'm Batman

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Joined: Oct 2004

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From: Springfield MO

St. Jude Donor '07

Quote:

Originally Posted by Durango_boy

I was reading a webpage the other day with some pretty radical bore increases for the CrossFire throttle bodies. The dual-injector/single body system was even used on 454s, so with the right injectors there shouldn't be a problem with upgraded throttle bodies.

Quote:

Originally Posted by KyleDallas

The CrossFire runners are only about half-height. I'd imagine one would flow pretty well if it was fully port-matched. The aftermarket intakes are pretty cool, too.

Oct 5, 2007 | 11:23 PM

KyleDallas

Drifting

Joined: Nov 2005

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From: Texas

Quote:

Originally Posted by I'm Batman

The CrossFire runners are only about half-height. I'd imagine one would flow pretty well if it was fully port-matched. The aftermarket intakes are pretty cool, too.

Manifold Flow Numbers
176 CFM @ 28" Stock CFI.
304 CFM @ 28" Offenhauser Cross-Ram.
240 CFM @ 28" ACCEL Hi-Flow intake manifold with Super Ram.
199 CFM @ 28" Stock TPI.

Height has little to do with flow capability.... cross sectional size and
port shape determine flow characteristics for the most part..

The Offy flows nearly twice the amount air vs. the Stock Crossfire manifold...
the Offy is a close knock off of the Z28/302 crossram.

Oct 6, 2007 | 12:24 AM

I'm Batman

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From: Springfield MO

St. Jude Donor '07

picture from the C4 forum:

Thread: http://forums.corvetteforum.com/show....php?t=1822513

That has to improve the airflow.

Oct 6, 2007 | 11:49 AM

mkj269420

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From: Clarksville Tn

I'm thinking if its a problem with air flow maybe then should do some mods on the on the bulky air cleaner cause really the only air that the tbs are getting is fron the duct through the hood. I can do wonders with sheetmetal and get more force fed air.

Oct 6, 2007 | 11:50 AM

Glensgages

Race Director

Joined: Jan 2003

Posts: 15,176

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From: State of Confusion

..... when I frequented Marck's Cross-Fire Forum, I believe Aussie Ben73 from down-under ran 12's with a Cross-Fire fed 383, but that was probably 3-4 years ago.....