[charlie66]

.0025 Is way too tight for a 3.25" main bearing. Even with a 3" main i wouldnt do it. especially for a boosted engine. I use to get caught up in the perfect number for crearances, but over the years of trying different numbers i realized that for the mains between .003" - .0045" you will have no issues.. One summer i broke 3 crankshafts. so each time i had new one made to fit my block it had different clearance numbers because the bearings are never consistent. This use to drive me crazy. So id call my crank grinder and try to have him grind it to get an extra .0001" off it if it was too tight . If it was loose i would get a different brand of bearing and try to fix it that way. Point is I found my self having to settle for a clearnce i didnt want and it never really made a critical difference as long as i stayed over .003" and under .0045" for the mains. I even payed close attention with the oil pressure at idle when hot . I thought it would be alot lower at .0045" then .003" But it turns out that it really wasnt.

Good luck with your build...