RBs From 65 up 440-6 only, 64 down Max wedge.
Same pistons year to year, no
I want to make sure I understand your information, so only 6 pack engines had pistons with valve reliefs from 65 up and only Max Wedge pistons had valve reliefs is 64 and older. And 440s did not use the same pistons from say 65-71.
Thanks
One example, 67 had the closed chamber 915 head, so the piston was down in the cylinder more. In 68 the 906 open chamber came about and the piston was raised to keep same CR. I do have some 70 standard pistons I can check against the 68-69 ones I have too, just got to find them, hope I didn't toss them. I can also measure the ones still in the 72 block, if it will turn over, never had any 71s so no idea on those. 70-71 6 Pacs where the tallest CH in 440s and had valve reliefs. Also have a 74 with low pistons, six-pac rods and steel crank, internally balanced, came out of a motor home, got its own balancer too.
