For me, it was upgraded rocker arms and push rods....Was wrecking pushrods and rockers like candy at .680 lift with our new 400/512 combo. Went to Comp SS rockers with more offset on the intakes, and Manton series 5 extreme push rods....Wow...Night and day difference. Never even took the valve covers off this year.

This for me also! I wasn't even looking for an improvement when replaced my rocker arms last winter. I was running the old MP blue rocker arms (alum roller, same as the Crane Gold rockers) but I broke another one at the last race of the season. I had a couple of spares, but when I started looking at the broken one and compared it to the other 3 that I had broken in the past few years, they were all broken in the same place. Upon closer inspection (w/ flashlight & magnifying glass) of the other rockers still on the engine, I found that 7 others were in various stages of cracking in the exact same place. At that point, I ordered a new set of Hughes rockers, which also required new push rods (Smith Bros.), After setting up new rockers & push rods, I was extremely impressed by the roller pattern on the valve tip.
Fast forward to this season, I finally figured out that the car had picked up WELL over a tenth of a second, closer to 2 tenths. At first, I just thought it was due to the weather, or track conditions or tire pressure or whatever, until I went to Clay City, Ky for the Mopar show in sept, and routinely ran low 10.30's (1/4 mile). I went back to my log book and found it was indeed running quicker than the last few years. Nothing else was changed on the car at all. Had to be the rockers & push rods??

Brian Dunnigan