General Category > Quadrajet Carb Talk and Tips
73 corvette 454 with a 17057216 and a spare 17080205
leroy:
Hello fellow quadrajet lovers
First the car 3500lb 454 781 heads 2 1/8" side pipes 1 7/8" straight thru's 16" vac@650rpm 38 degress all in by 2800rpm, ported advance. Intake has no branding I can see but is a duel plane ali job. Guessing stock compression and cam unknown, starts to fall over at 5400rpm. 4 speed 3.55 rear 27" tall tyres.
Bought this car in Australia and had only been in the country 4 months , appears to of had a frame off rebuild looking at it but can not tell your much more about the motor.
Now the carb. Hurts me to tell you this but it is a remanufactured one from somewhere( the air bypass was blocked off with lead plugs could not see numbers on jets, primary rods looked like 41B (was there an E?eyes not as good as used to be) , 110 inlet, DP secondary rods and one of the full vac ports was missing a tube and not blocked off)
Anyway dived in everything looks nice and clean, blocked off the vac leak checked throttle plates sealing off properly when closed, did the secondary lock off at 90 trick and confirmed apt screw was operational (this one in the throttle plate)
Drilled the mixture screws out to 90 thou air bypass closed up and set to 50 thou from the spare put in the needle and seat being a 130 put the 72 jets and 51M rods and DR rods
Anyway smooth idle and nice transition to primary and happy with the secondary side but still need to sort the primary side i reckon it is still too rich usind tip in method
soo want to buy cliffs primary rods and DA rods but what jet s , oh the air bleed is 55thou
Cliff Ruggles:
"M" series metering rods would not be correct for an early style carburetor with the APT in the baseplate. They are too short, and the tips are too fat.
The "M" series metering rods were used in the later single main airbleeds carburetors, with the APT just in front of the power piston.....Cliff
leroy:
Thanks for the reply Cliff
Guess I will put the 41B that I have back in then
Given what you have said looks like I will not be able to use your 44 rods then
Was thinking since it was a 170 series carb the M would be ok but glad you sored me out
What are your thoughts on jet/rod combo would work given the car its in
Thanks again
Cliff Ruggles:
If the APT system is in the baseplate, they use longer metering rods, with .026" tips. They made Chevy truck and Marine carburetors with 1705XXXX numbering that were still the old divorced style units that used longer primary metering rods.
The later single main airbleed models with the APT in front of the PP, used "M" series metering rods.
They can also be set up with our "44" metering rods and smaller main jets.
We sell the correct length rods for the early carburetors.....Cliff
leroy:
Yep the apt is definately in the base but looks to me that it has the single main air bleed
Does that sound right or has the airhorn been mismatched to the body . I know the number on the air horn is different to the body
Righto so a set of primary rods to suit from cliff but what jets just wondering if I need to go smaller than the 71 in recipe 1 or maybe just a softer PP spring.
When I floor it it does stumble a bit and then up and away but it does leaves two puffs of black smoke behind me and is not the tyres any advice is appreciated
Cheers
Leroy
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