In the high comp motors it was always done with the heads and head gasket thickness as you can clearly see when you look at a factory parts book!
Other wise the factory would have had to have a incredible mind boggling number of different piston fitted service replacements blocks to make and keep in stock for shipment!
For example , in 1970 in terms of the 400 motors that where not RA4s there where 3 different compression ratios for these motors, yet there was only the 479879 service replacement block listed for all 400s including the RAIII motor.
From 72 to 74 there was only one 400 cid service replacement block listed in the parts book.
Only on the mid 70s did this change somewhat when the factory began to add a chamfer to the top OD of some of the pistons to lower the compression yet even more then what the already big chamber heads did.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!
1) 1940s 100% silver 4 cup tea server set.
Two dry rotted 14 x 10 Micky Thompson slicks.
1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.
Education is what your left with once you forget things!
Last edited by steve25; 09-15-2021 at 05:51 PM.
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