General Category > Quadrajet Carb Talk and Tips

7040202 APT

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mcx:
Hello Cliff...I picked up another cheap QJET from ebay this time...its a 7040202 and supposed to from 1970 350 auto Chevelle/Camaro/Corvette...it's a bit crusty but came apart easy enough and it seems all there...it's different from other two(Buick/Caddy) in the  air horn bleeds are not the small "bushed" type... and that the APT is set so low it's flush with the base plate, it's not even up to the gasket?  Is this how it came from the factory, it would seem the primary rods would never get out of the jet?...anyway, it's soaking in Wd40 as it is buried in carbon.   Thx, Mike

Cliff Ruggles:
1970 was the first year for the large MAB's on the Chevy units.  They stuck with that for a few years then went to SMAB on the divorced carbs in 1977 an 1978 (truck carbs).  The larger MAB's were finally phased out by 1980 and the SMAB was used till the end of production on the non-CCC units......Cliff

mcx:
Thanks Cliff...I know the factory  APT settings are differant from application to application, but is it common to see no primary hanger lift ,as this one?  The primary rod piston bottoms out? Thx,Mike

Cliff Ruggles:
Yes, I've seen them from no lift at all to up pretty high on the same part number.

Those units were factory tuned and why we like to remove the stock APT screw and use our adjustable one with a spring on it to hold it's adjustment.

They can be a PITA to get out of some baseplates, but well worth the effort.......Cliff

mcx:
Cliff...this 7040202 has no ported vacuum feature...you see any issue with me carefully drilling a passage in the main body and in the correct spot in the base plate? Thx,Mike

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