General Category > Quadrajet Carb Talk and Tips
#7044270 Secondary POE Restrictions
Brian B.:
Hello. Would anyone kindly be able to confirm what the below factory stock measurements should be for a '74 SD. AUTO 7044270? Thank You.
Secondary POE Well Restriction
Secondary POE Restriction
Secondary Tube Restriction
Kenth:
Hi.
In my notes on 7044270 i have:
Secondary POE Well Restriction .034"
Secondary POE Restriction .077"
Secondary Tube Restriction ..049"
I spent an afternoon tuning a friends 1974 T/A 455SD using a racing camshaft and i could not have proper WOT respons with the closed airvalves on this unit. Replaced those with the earlier airvalves that has the large cut-outs and the car ran like a demon thru the gears. Owner went home with a big grin all over his face.
Final jetting after this session, #75 jets (.076"), #45 pri. rods, .041" idle tubes and .066" idle down channels. Also CC secondary rods, K hanger.
Cliff Ruggles:
CC secondary rods are HORRIBLE, too fat up top and too small on the bottom. I refuse to use them for tuning as they need a pretty tall hanger to get them up out of the jets holes quite a bit to get a clean transition going to WOT.
I've actually had better success removing the notched Pontiac flaps and installing solid ones that the other way around IF the holes were under the flaps or directly in line with them with a large opening exposing some of the entrance under the flaps.
Another neat trick when tuning the secondaries is to leave a very slight amount of slack in the linkage so it can "tip" back just a tad exposing the POE holes to the underside of the flaps and fuel from the holes directly to the intake........Cliff
Brian B.:
Thank you gentlemen.
Kenth.....did your friend leave the Secondary Restrictions stock or were they enlarged.
Cliff.....do you prefer rods along the order of AX or DA?
Kenth:
We left the restrictions at .077", which are the largest to be found in any Quadrajet and common in Pontiac high performance carbs.
Also, we found the initial discharge was improved going to the cut-out air valves making the CC rods actually worked as intended.
High numerical rear end gears and high stall converter may have helped jetting with CC rods in this 455 SD engine some.
Respond at WOT was instant w/o hesitation of any kind.
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