bbc main bearing clearance with aluminum block????????

[badbug3]

On an aluminum block with billet steel splayed main caps, does the main bearing bores get tighter or looser when heated up to operating temperature ? Would you just shoot for the same clearances as on an iron block?

Therefore, what main bearing clearance is desired?
Application being drag race, recreational marine use, fresh water , cold block temps of 100-130 degrees operating temperature.
Also being turbocharged. thanks

[superstreeter]

I put a beast like that together last year,,,what a headache,,I set all the clearances the way you would a steel block,,,but everything expands more than the steel block,,You will probably find when you fire it up that your oil pressure really drops when it gets warm,,also had problems honing the mains (alum/steel) more problems for sure than steel! but once you get past that, you`ll probably like it.any other questions, just let them rip!