Mileage + Go = 17057229?

[A. G. Olphart]

When I found this small casting Qjet, that was the hope, but it seems to be an odd one:
Single main bleed (air horn)-    .050
main body upper idle air-           .076
lower idle air-                               .060
idle down channel cup                 .046
idle air bypass                               .140 
primary jet                                     64     
primary rod                                    39B
sec. hanger                                      K
sec. rods                                           DG
Then I found Cliff's mention that the single main AB carbs can be hard to tune.
Should I even try with this one? 

Instinct says the small castings  with higher primary flow should make better mileage than the larger castings, and 750CFM seems big enough.

Carb is for a 60 over 350SBC with good aftermarket heads, a Voodoo 60102 cam (219/227 @ .050, 16" or more vacuum per the designer), and block huggers.
Approx 2500 pound car, 3.7 gears, OD trans with locking converter.


I also have another oddball carb,  # 17084502.    My guess is that it was a marine carb because one main well bleed tube and both sec. accelerating well tubes were evidently shaken out of the air horn (found loose in the main body).
73 jets, 49V rods (that's right...  'V')
T hanger with DH rods.
There is also a deflector on the bottom of one sec. air flap. 

Any chance for decent (20s) mileage with either of these and a stock 72 Chev pickup intake manifold?
Got a Chevy huge air bleed carb too: 17054929.

Which way to jump...


Thanks guys,
A. G.

[omaha]

I think yu will be ok with the 17057229. I dont know what those primary jets would be used for and what rods would work with them but for fuel mileage. Idle bypass is large, prolly was on a sbc 400 engine.
fuel mileage is all about main jet selection and rods/piston-spring combinations and learnin to keep your foot out of it.

[Cliff Ruggles]

Sounds like you have found one of the early divorced choke, small bore, single main airbleed carbs.  They are nice units, and if you can free up the APT screw in the baseplate, a good choice for what you are trying to do....Cliff

[A. G. Olphart]

Thanks, Omaha, Cliff.

Guess I'll go with the baby carb.  The big idle air bothers me, but I can swap the baseplate with my other 1705 (it has .125 idle air) if there seems to be a problem and see if it helps.

Cliff, this carb no longer has any finish on it; do the numbers I've shown seem consistent / compatible? 
Also, your book mentions that these are hard to tune.  Any specific problems or tips?
Should I just clean it, kit it, and give it a try?   

Thanks again...  I'll be calling for parts.

A. G.