We've been 1.34 @ over 3950lb with AFCO D/A's all round. We used to have the Rancho 9 ways (Rear) and comp engineering 3 ways (Front) combo. Car would sometimes wheelie and we'd lose around .1 off the ET, not good when you're bracket racing blush . We also tried the Calvert front shocks and like Chip found, we also thought them too loose for a heavy car. Sold them to a guy who put them on a much lighter A body (Duster IIRC), they had better results.
We've also had the AFCO's re-valved by Menscer as we basically ran out of adjustment on the rear extension damping. This was done on front and rears. We've only done 6 passes since and now we're chasing a bog on the tunnel ram, we were getting there but we ran out of race season smile . Data shows the car is a lot more consistent with the D/A shocks.
HTH's up

'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge.
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03