Originally Posted by 427Hotrod
I saw some dyno tests on them in Hot Rod a long time ago...they made beween 425-440 or so on engine dyno. The later versions of them actually went to a hyd flat tappet copy of the LS-6 cam with non adjustable valvetrain. In the dyno tests they were essentially a dead heat between the two cams. But they were only revving to 5200-5500 rpm or so.
I saw an old Hot Rod test where they dyno'ed a Mark IV LS6 Crate engine and got 437 HP.
I was still curious at what GM rated the torque for this engine at, with the 1970 Chevelle LS6 coming in at 500ft lbs with an 11.25:1 compression ratio and the 1971 Corvette LS6 coming in at 475 ft lbs with a 9:1 compression ratio.