[kerber63]

Do you happen to know if the input shaft was changed to a LS1 style? Older bellhousings are deeper than the stock one from the LT1, so a longer input shaft would be needed to seat properly in the clutch pack. If it has a LS1 shaft, a mechanical clutch can still be used with a standard 168 tooth flywheel.

However, if the input shaft is still from the LT1, you're in for some work. You'll either have to convert to the LS1 shaft, which involves removing the front cover of the transmission, or put the stock LT1 bellhousing back on and toss (sell) the conversion plate.

Pros to going with the LS1 style: you can keep your stock flywheel and use a conventional push-style clutch, either mechanical or hydraulic; you can use your stock starter. Cons: the deeper bellhousing pushes the shifter back a little bit further than the stock LT1; unless it's already done, converting to the LS1 shaft can be challenging.

Pros to going with the LT1 style: the only conversion piece needed to mate to the motor is a custom flywheel. Cons: a LT1-specific pull-style hydraulic clutch has to be used; a 153 tooth starter has to be used.

I chose to stick with the LT1 setup just because I didn't want to strip it down just to use a conventional clutch.