hi im new to this site. but anyways we just picked up on a69 bonneville with the YH 428 in it. it probably needs a rebuild unless we can get it to turn over. i have a 76 formula 400 4 speed that i was hoping to build up on the engine anyways so right now it would work out good. but me and my dad are wondering if anyone knows what it would take if we rebuilt the 428 with 62 heads and make it to the stock 390 hp version from 69 to make my 76 run 12's. also if anyone has any info on where i can find 62 or 12 heads and any other parts for our 428. thannks