Tremec 3550 swap?

You would simply use a regular 360 flywheel and pressure plate, and a disc for the 3550 in the correct diameter (10.5"). I'm not sure if the TKO conversion parts are the same, but if not you can buy discs and pressure plates separately from just about any clutch supplier--my Valiant has a McLeod pressure plate and a RAM disc. I'm not certain what you'd do about the throwout bearing, though. I'd look to see what's being used in TKO swaps and check the ID against the front bearing retainer of the 3550. My guess? Same part.
Before you start doing too much research, though, I'd suggest checking the shifter location on the 3550. Do some measurements and make sure it'll come through the floor in an acceptable spot.