Hi everyone

Wanted to provide an update on the 350cfm carb tuning.

I put in 58 jets (smallest I have at the moment), put in a 28 squirter and pink cam.

Confirmed timing and then started to adjust the idle mixture with a vacuum gauge. 19" vacuum was where I dialed in the best value. In drive I had 15". So I put in a 7.5 power valve.

I did some quick tests in the driveway and noticed an off idle bog. I started to increase the squirter nozzle and went to 31. The bog was there but less. Moved to an orange cam and bog disappeared in the driveway in park.

Engine at idle still a bit rich 12.5-13.0 - so initially I am guessing I need to move to smaller jets.

Driving around noticed a significant improvement, however still having a bog at cruise when I accelerate. My AFR gauge went up to 19 from the 14.9-15 at cruise.

I moved to a blue cam with no real improvement. So I moved to a 35 squirter and an orange cam.

I noticed somewhat of an improvement here. Is it normal to need this much pump shot? FYI the intake I am using is an Aussie speed Hurricane.

I think I also need to move up to an 8.5 power valve.

At cruise, I still observe a bog from 1100-1600 rpm before the engine rebounds. Above these rpm's it is much less although still there.

At highway speeds, AFR is 14.9-16.0 (around 2400 rpm) and I run lean when all in on accelerator (17.0 - 18.0 which is why I think I need an 8.5 power valve).

All told I know I have moved to better. An 8.5 power valve will certainly help on my top end, but I don't know that I will be able to improve my transition circuit any more on this carb.

But Dusteridiot, I have to say you are right, so thanks for your help.

I think what I am seeing is the limitations of this carb on my setup. I am having low-velocity issues at lower rpm's and while I seem to be able to find a better tune it is still far short of where I need to be.

A Holley 390 cfm 4bbl will be forthcoming this winter.