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Dagger
03-01-2007, 10:55 AM
I've got a buddy looking into a Quick Fuel Q-750 4150 style carb for his 67 Shelby GT350. The carb is a 750 cfm with mechanical secondaries, billet metering blocks and baseplate, along with a host of other mods. Anyone have an opinion on the their carbs? How would this carb work in this application:

The motor is a 348 SBF with a period correct Paxton supercharger running 5-6 lbs. of boost max. The carb is encased inside the stock sealed paxton air box. I believe it has iron 289 HiPo heads and is running about 10.25:1 compression. I can get the cam specs if needed.

Shaker455
03-02-2007, 09:11 PM
Dave,
The QF uses Proform parts....not the best quality.

If I was to recomend a few I'd say Bolaws, AED,

ProdigyCustoms
03-03-2007, 05:35 AM
I actually had good luck with QF the couple I used. But gien a choice, i like a real holley. Also, since it needs blower mods I would look to a custom builder of a Holley

HILROD
03-03-2007, 10:17 AM
Quick Fuel now sells blow thru carbs. I haven't seen any info on them, or anyone running them yet.

dhardison
03-03-2007, 10:48 AM
I agree that most ProForm parts are not of the highest quality, but I have a QFT 950 with the ProForm main body and so far it's been an excellent carb.

Shaker455
03-03-2007, 08:40 PM
Frank & Dan,
I know QF is not Proform but they're buying a lot of there stuff to market and I also know that some of the former Holley engineers formed QF and they are good people over there.

I built a custom carb for 69taposer on this board using a Proform 950 mainbody and the rest Holley parts with the transition circurt jetted and it ripped!

What gets twisted is they're 950's venturi is close to the size of a mighty demon 825 of 1-29/64" (1.453")

Just an FYI:
I recently reworked a proform 850 with they're billet blocks and base, it seemed anything that was purple need more attention than it was worth.

What I did not like was the venturi size was that of a 750/ Holley HP 950...1-3/8"X 1-3/4" vs the standard 850's 1-9/16"(1.562")x 1-3/4 with no shear step in the downleg boosters.

I ended up resizing the venturi's slightly larger than a 850 and installing new Holley HP 850 boosters with a shear step for better atomization.

Also the primary throttleshaft tapped holes for the throttle plates were drilled so far off center that there was no room for adjustment and was not allowing the blades to return down far enough to cover the transfer slot properly.

I know the CNC billet blocks look great but the more I work on them for customers the less I'm liking them over the standard Holley cast units which because there cast there is no burrs inside.

When they drill holes into the main wells it creates burrs and chips that are not removed which results in poor preformance and tuning.

Long story short after much effort to correct them I sent the carb back to the customer with a pair of my blocks that I use when I build a custom Holley of this size....

It was the best choice as the blocks had adverse reactions to minor changes and I did not want to hand it over to the customer like that as I guide all my customers thru tuning.
Jeff