I have many 68-76 buick big blocks. Are there any differences in stock flow characteristics ie which is the best head excluding stage 1 heads to run unleaded with? Of those years, which is the best block. I'm temporarily putting a 72 455 in one of my 68 rivieras. Hope to hear from someone.
No difference in the heads from 70 to 76 in that sense. For purposes of lower octane fuel use the compression ratio was reduced in 71 by using a different pistons. No special prep is needed to run unleaded fuel although some still argue you need harded valve seats. I have never seen anyone report a problem with a Buick head because they did not. For 455 heads 70-71 may be the best and they all can be made to accept the bigger stage 1 valves. The new TA aluminum heads are by far better they even the competition ported iron heads almost right out of the box. There is believed to be a better rocker ratio on some 430 heads but people report there is some mods needed. The later 75-76 455 blue blocks are believed to have the best castings for meat and core shift.
