It'll probably work, can you estimate the length of throw, and where the sliding collar starts, relative to the end of the input retainer snout?

You could run a longer body to the throwout bearing holder. The input retainer snout you pulled -- is it the same OD? How do the retainers that you have vary, exactly (clearly length, but what else)?

If it proves to be a problem, you could have a shop surface the front and rear of the bellhousing on a mill -- simple setup, so it should be pretty reasonable, price-wise. Lots of options are available -- part of the joy of rolling your own! <img src="/forums/images/graemlins/pfft.gif" alt="" />

Randii