Anyone have any input here or have this same experience. Since my build 292, bored .030, pertronix 2, header, mumert intake, summit 600 carb, original 4 speed T98...
My engine builder installed autolite 46, after about 6 months i put in 45s as it seemed to be the preference for some longer highway driving. Which I do from time to time but not often. Somehow my engine seems to lean out and stop pulling around 2800 rpm. I have checked timing, trid different carbs. Something is up and I am not sure what. I am thinking I might put the 46s back in. what is the best gap for the 46s? Thanks folks.

What  a bout a  vapor lock That would cause  the problem your talking about, and  highway driving  is prime time for it to happen!