I got the setup right for the conditions around Noon on Sat.
I richened the fuel slightly, and made some minor chassis adjustments for controlling the expected power with the right weight transfer and wheelie bar setting.

3200 lbs
511 CID low deck (400 block), 4.250" stroke
Indy 440-1 heads, Indy 400-3 (4500) intake
Ron's Flying Toilet (4.1") mechanical injection system. www.killerrons.com

As far as the bullet mufflers go, I did a back to back test last year. The headers are 2-1/8" x 32" long primaries with 4" collectors. The first pass was with the open headers. The second with the 4" dia collector extensions (~18"). The third was with these 4" dia bullet mufflers. The first two were the same, and the muffler run was only 0.02 seconds slower than the others. See the timeslips attached.