The problem is with the clutch fork that needs to be used with the my 10.5 inch bellhousing. From what I can tell, this same problem might happen with TTI's as well. On the standard early A-bbody 10" (vs. 10.5") bellhousing and clutch the fork is much smaller and it tighter into the motor. The fork I have to use with the 10.5" clutch is longer and hits the headers.
As for the lakewood bellhousing, is this used with a 10" or 10.5" clutch? I wouldn't worry so much about the bellhousing, but the fork and z-bar.