First plug change.

IAB .073
HSABs are .030 pri/.033 sec
.059 PVCR
The air around here's been so bad I haven't wanted to do much after work but it's improving so I want to get out for some test drives the next few days. Thanks for the input guys, gives me some good ideas on what to look at first.


Roughly, if the IFR mentioned above is correct, I’d either be about .008-.010 bigger on the IAB or down to .029-.030 on the IFR.

When you get the idle circuit clean like it should be, you’ll have to fix the rest of it...it will likely have tip in issues and at the end of transition it will go rich, so that’s where the T slot restricters come in the most.

The smaller the MAB the later the booster gets going, and the fatter the fuel curve will be at RPM. The larger the MAB, the quicker the booster starts, and the leaner the fuel curve will be at RPM.

One interesting thing...and I’m fighting it right now myself is with lots of cam timing and relatively low idle vacuum you get another issue that acts like a lean tip issue, but it’s really a rich condition.

Once you are moving and the vacuum goes UP, but you are still on the idle circuit, because the vacuum signal is greater...you are now back to rich going from idle to transition, just like you’ll be rich from transition to the mains! This can get you in the weeds (I’m still in the weeds but they are no longer strangling me...I’m starting to get a handle on what’s happening) and drive you nuts.

This is magnified with a tunnel ram, but still a issue with single 4 stuff. What may “drive” and “feel” like a lean spot from the idle circuit to the T slots is really a rich condition, because the signal (i.e. the vacuum is higher but you are still on the idle circuit) is much better.

It can be hard to wrap your head around this, but it is true. Lucky for me, I have the BEST carb mentor, who is willing to help me along.

Otherwise, I’d be screwed.