B/RB height in A body

I was wondering pretty much the same thing. Small block 340 though just put engine and tranny in and it was lower by about 1/4" on passenger side . I shimmed it got it level .and put the headers on yesterday.HOLY SH#T!!!!! WHAT A TASK THAT IS! First time putting headers on an abody have always had Rams and ramcharger. 5 hrs. By myself