Author Topic: 1000+ cfm from a Qjet  (Read 1748 times)

Offline 70GS455

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1000+ cfm from a Qjet
« on: April 16, 2024, 12:59:59 PM »
I ran across this article from David Vizard in his "How to Build Horsepower", Vol. 2. They discuss the mods required to get 1090 CFM out of a Quadrajet.

Offline 70GS455

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Re: 1000+ cfm from a Qjet
« Reply #1 on: April 17, 2024, 05:26:56 AM »
Here is a pic of the first page

Offline Cliff Ruggles

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Re: 1000+ cfm from a Qjet
« Reply #2 on: April 18, 2024, 01:33:14 AM »
I haven't seen any of that before but two things for sure.  It is outdated and much of it is not accurate.  Bronze fuel filters weren't used past 1967 for example.  4-6 psi fuel pressure?  The later units will easily work with nearly double that pressure as they moved the hinge pin to provide a LOT more leverage on the fuel inlet needle. 

Thinning throttle shafts and knife edging throttle blades, pretty much a waste of time and the primary shaft is really thin right to start with and delicate enough as-is.

I'll stop there, but most likely that was written quite some time ago and not really detailed enough to provide much help for setting up one of these carburetors for big HP applications......FWIW....

Offline novadude

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Re: 1000+ cfm from a Qjet
« Reply #3 on: April 19, 2024, 12:26:19 PM »
I agree that thinning throttle shafts would not be very practical.  Not a lot of material there already... would probably be super fragile if you cut them down more.