[SD455DJ]

We made 14 pulls (3000 to 5500 rpm) in 2 hours and were pleasantly surprised with the results:

Corrected (Uncorrected): 383.9 hp (357.5 hp) @ 5300 rpm and 454.1 lbft (425.4 lbft) @ 3600 rpm (pull #11 with the highest torque). Pull #12 (no changes – back up for pull #11) netted the highest corrected hp at 384.7 with max torque a tad lower at 452.5 lbft. The highest average power was pull #12 at 343.8 hp and 423.7 lbft torque through the 2500 rpm range. We were surprised how the power hung on to 5500 rpm (the TH400 trans governor is set up to shift at 5600 rpm automatically).

The timing was set and left at 36 degrees for all 14 pulls. The exhaust system off the manifolds was Pypes 2.5” mandrel headpipes tied into another 8’ of 2.5” flex and straight pipe (12’ total length). The 7041264 Q-jet started with 73 jets/43 rods on the primary side and CC .030” M tip secondary rods on a ‘K’ hanger. The secondary rods were changed 4 times more getting leaner with every change…to CE - .0410” M tip; then DR - .0570” M tip; then CL - .0667” M tip; and finally CG - .0774” M tip, which were the leanest we had and still a tad rich. We then swapped in a ‘T’ hanger which leaned it out enough for decent BSFC’s (0.467 avg.).

The max corrected hp/tq with the 2.5” exhaust pipes was 380.7 hp/451.1 lbft. The most power (pulls #11 & #12) were made with the Pypes headpipes dumping into big 6” diameter straight pipe and swapping back in the ‘K’ hanger on the carb. It didn’t like the baseplate on the carb and lost a 4-5 hp and tq.

Oh, we used a 50/50 blend of 93 octane and 110 octane gas just to make sure we didn’t have any detonation as the knock sensor wasn't working. The motor ran beautifully without a hiccup or any blow-by. The rings are definitely seated now.

Dennis