General Category > Quadrajet Carb Talk and Tips

7045230 for Pontiac 468?

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Marx3:
Hi, would this carb be a good object for a 468 pontiac (1973 455 ) ?
engine has 7M5 114 cc heads, rpm intake, and a 278/290 adv. dur. Crane cam, M21 and 3.55 gearing.

Upon disassembly i discover that this carb has the 3 brass tubes in the airhorn, plus that extra jet/rod in front of the powerpiston ( I thought I would never see this )

Now I have doubt as to how good this carb would be, even if it is an 800 cfm unit.

If it is good, I am thinking recipe 2, as of now ( 650 Holley ) it pulls 14-15 Hg at 800 rpm.

thanks,  Jacob

Marx3:
No one knows if this carb is worth rebuilding for bottom-end Pontiac power?

Cliff Ruggles:
Those carburetors are just as good as any other late model large cfm q-jet.  They are more difficult to set-up, using the early styel APT system and auxiliary Power Piston.  We block off the auxiliary PP and install larger jets and metering rods, the rest of the rebuild, recalibration, etc is the same as any other late model unit, and well described in our book.....Cliff

Marx3:
Great, so it will get recipe 2.

It has:

jets: 60
rods: 35J

Hanger: N
Rods: DH

Which of these would you change to what, if all bleeds an channels goes according to recipe 2?

Marx3:
btw, I have your book ( my Qjet-bible! ), and have already built 4 or 5 carbs to recipe 1 and 2, I just need guidelines for the jet/rod-size, and I will be quiet :-)
If I need jets/rods for this rebuild, I will order it from you.

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