[blykins]

I set aluminum block main bearing clearances pretty tight on FE's...usually around .0018"-.0020". Taking into account that the clearances open up anywhere from .00075-.001".

Rod bearing clearances are the same as an iron block. Cam bearings get the green loctite treatment.

Lash also grows a lot more with an all-aluminum combo. Iron blocks with aluminum heads get .006" tighter lash when cold as a starting point. All aluminum engines get .010" tighter.