Question about a trans I have.

Confused about the rear timing hole? The majority of the RV 727s had a timing hole cut into the top of the bellhousing and timing marks on the original converter.

As for anything HD in either of the transmissions, probably the only thing in both, that would be considered "HD" would be a factory 4 pinion front planetary. You should be fine at that power level with that planetary, and a trans-brake, unless the car is going to be freakishly heavy for some reason.