We snapped an o/p shaft when a ring and pinion failed (Dana). We replaced both the i/p and o/p with H/D ones on the rebuild and it lived behind a 900+ft/lb 655 wedge with no apparent issues. Long term, we intend to switch to a TH400 derivative box and a 9" type rear.
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'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