If you're easy on the changes you could have 400rwhp and have no slip with a s**t clutch.

I would have had about the same power when I munted a few XR/heavy duty spec clutches. They dont hold too well flat shifting 1-2-3 on limiter with 245 rubber. I snapped a couple of cables.
Exedy 5 puck button clutch on the other hand had no drama, even with a turbo strapped on the side.
I snapped cables, busted bellhousings (should have got a pic, split it in half), bend pedal boxes etc.

Ive now installed a hydraulic setup with a semi organic NPC clutch rated to something like 400rwhp. Havent been able to test it yet tho