If the 01 = Mach 1, then I wouldn't go over 400-450rwhp. The mach 1 engine does not have forged internals, the most you want to push on them is 400-450 to be safe. you MAY be safe going a bit over 450, but I wouldn't risk it if you want the engine to hold.
The 01 cobra and mach 1 blocks are...