Q-jet runs great but lean,(race car)

[Mr.Pontiac]

ok, i am running right off jets 66,s my q-jet running great!!, electric pump flowing 6.5 psi to carb. but after a run down the quarter mile plugs are getting fouled, dark black and smells like gas. I installed 65 jets now the new plugs are all white as snow as if not even burning correcly. Float at 1/4. Carb. no is 17056240 single air bleed top. Carb. has gotten me to 11.90,s at 108. any advice here air bleeds opened up to .110 base plate. Running no metering rods, running straight off jets. Thinking about running it at 7 psi to see what happens. any advice? small float installed, filler cup ground down for more fuel. Running your needle and seat for racing.

[Cliff Ruggles]

Going down one jet size isn't going to go from being pig rich to too lean. 

You have a fundamental problem someplace not related to the small change in metering area on the front jets.

I'd lower the float to 9/32" if you are using a .140" or larger inlet seat and see if it helps some?.......Cliff

[Mr.Pontiac]

If i sent carb. to you would you check it out quickly for me??? Nationals coming up soon!!

[Mr.Pontiac]

On page 30 of your book, where PCV tube is sticking out about 1/2 to 3/4 of a inch is broken off in the area behind where tube go,s into base plate. Retapped for larger tube and broke thru. Wondering if this could be causing me a massage vacum leak and causing my problems.??