On centerforce's (rather nebulous) instructions that they give for testing the parallelism of the BH mounting surface, they state that the maximum out of parallelism is .002". The total travel that I got between the lowest and highest points on the mounting surface with the indicator about 3/4" away from the bore was just under .004".

Can I interpret that as being within the tolerances? In other words, is it correct to say that the bellhousing face is .002" below true parralel on one side of the centerline of the bore and .002" above true parralel on the other and ok for use?

 

no idea what it should be for your application. in general to answer, or try to answer, your question it would really depend on how they speced it. as you say you're within .002 of the datum point, -.002 on one side and +.002 on the other, but also .002 out if it's from side to side. it really comes down to what they or you use as a datum surface.

 

I was assuming that it would be the intersection of the centerline of the crank and the plane that defines true parallel for the mounting face. It would be nice if they elaborated a little as to what they wanted. Ill probably have to call them and get some more details.