Equal length headers to 340 manifolds. Re jet carb?

Title says it all. I think I am running a bit fat now. Where would you start? 2 sizes down or more?

I now have 76 fr, 74 rear in a Holley 800DP. I also have a Holley 750 vs and the org 625? AVS to play with. The AVS is to small.

68 340, ported and flowed X heads, 11.7cr, Crower solid street roller, 4 speed, 3.91 rear.

Best time with slicks, headers and 3" exhaust 11.78 @ 118, best time with manifolds, 2.5" exhaust and E70-14 Redlines 13.2 @ 105