carb rich

[17058263]

1977 qjet with. 73 jets. with 49 k rods. carb works great at all rpm. but if i am on the free way and i hit the 2bbl side i get a puff of black smoke. then it goes a way. throtle response is great. and off idle is perfect. engine is pontiac 301. 60 over.

[Cliff Ruggles]

That carburetor was set up quite a bit leaner than you have it on the original 400 cid Pontiac 4 speed engine.  Pretty sure they had .070" main jets and 41 or 42K metering rods?

Anyhow, it may help to take it back to the stock configuration and see how the little 301 likes it?.....Cliff

[17058263]

the carb number is 17057256 pluge dont show any sing of rich ness. but my tail pipe does  have some black soot. but not a lot. and my fuel econmy is bad

[17058263]

i found out the problem one main air bleed was 41 and the ohter 28 i i found anther 0.41 put the float level to 16/00 and she runs great and took it 20 miles each way on the free way and did not burn any gas. quadrajet for ever