Nightmares, 1966 Chevelle original SB w air, was changed to BB at sometime,now owner wants SB back in it, he kept original 283 but no brackets etc. 396 w turbo 400 back to 283 w PG....crank balancer has the rivets in place,need a 3 groove pulley for it. Not finding any with extra holes for rivet heads...Choices are drill it to accommodate the rivet heads or grind the heads flush.........also has newer METRIC type PSpump, so another bracket challenge......... Any suggestions :-) thanks