DeTomaso Mailing List: July 97, Message #179
     



From: "D.Jones" <m203253@ws2200.mdc.com>

Subject: Re: RE-SEND 351C Intakes Test

Date: Thu, 10 Jul 1997 17:26:31 CDT



> I'd believe the numbers but don't expect to duplicate them, real-world-wise.

> Those carbs are gigantic! Everyone knows that as you upsize carbs on a

> Cleveland, power increases, gas mileage drops, throttle response gets longer

> and driveability goes down the 'porcelain convenience'. I'll give up 30-40 hp

> for instant low-end. J DeRyke



Holley carbs are primitive devices and don't tolerate over-sizing very

well.  They're great at wide open throttle but leave much to be desired 

the rest of the time.  By comparison, the Carter Thermoquad was the end 

of the 4 barrel food chain.  Introduced in 1971, the TQ is a much more 

sophisticated carb than the typical Holley.  It has a spreadbore layout 

with tiny primaries and huge secondaries.  The primary jets are variable 

area by virtue of a vacuum referenced, spring loaded, rod and jet 

arrangement and employ dual concentric boosters.  The secondaries have 

an adjustable, shaped, flapper door that provides a pseudo variable venturi 

effect.  There's even an altitude compensation gizmo.  The small ones flow 

800 CFM and the big ones are rated at 1000 CFM.



Rochester Quadrajets are similar to Carter Thermoquads and I've 

successfully run a 750 CFM Qjet on a stock 8:1 compression 3.8L Buick V6.

Try that with a Holley.  I've got a couple of TQ's that I'd love to try 

on a 351C but unfortunately Ford's 4300D spreadbore pattern is not 

compatible with the TQ/Qjet.  If I ever come across an aluminum 351CJ 

manifold (anyone on the list got one gathering dust?), I'll see if I can 

modify it to mount a TQ.  The other option is Offenhauser.  They offer 

most of their 351C intakes with a spreadbore pattern.



Later,

Dan Jones



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