You definitely want to dial-in the bellhousing, regardless of the manufacturer.
http://www.lakewoodindustries.com/pd...USINGALIGN.pdf
Some people believe that some bellhousings (Quicktime is often mentioned) are machined so accurately that you can skip this rather tedious process. Don't believe it! Even if the dowel holes in the bellhousing are perfectly located (which is doubtful), how can you be sure the dowel pin locations on the block are equally as perfect?
Remember....0.005" runout is all that is allowed...and that ain't much!
Rodger