[A26B]

Todd,
I had this very discussion with Graham last year at BG. You were there too, sure wish you had been there for the talk-about.

Summary: Torque to yield doesn't actually mean the bolt exceeded yield strength and suffered permenant deformation which would occur if yield had been exceeded. The differential thermal expansion rates of steel & aluminum would however, place additional longitudinal stress on the bolts, for which no empirical data was ever obtained. It could be calculated but would probably assume "0" deformation under the bolt head or through the thread engagement.

Bottom line: Graham didn't think there would be any adverse results from reusing them. FWIW, this same line of thinking also applied to the head bolts.

He also went on to say that he was opposed to increasing the main bolt dia because of the possibility of encountering casting porosity during the bolt thread enlargement. It would be difficult to determine and would result in potentially catastrophic results.

Having said all of this, I feel confident that Graham was probably thinking along the lines of a stock or mild rebuild. Considering what you are doing, this bit of info probably doesn't have much value to you, except for the larger main bolts/studs.