My pleasure. I cant tell you have many times guys will tell me I am wrong about the motor changes in 56. Many, like yourself just missed it in the manual or never read the 56 supplements to begin with. I have been playing with these motors for 47 years so while I may not know everything or even a lot, I know enough, lol. Truth be told, I steer clear of the 55 production year blocks just because the 56 and up were so much better. Frankly, the 56 motor, with its 848 head dated 56 is a really great candidate for a 55 swap in that the 56 head has has the temp sending port the same size as the 55, so its a direct swap, whereas the 57 and up use the larger temp port (requiring adapters). The 5913 head has a combustion chamber volume of like 86.2 cc where the 848 head is 79.1 cc. The benefits of course are, higher compression, better HP, neoprene rear main seal, precision bearings.
Last edited by Dragsix; 10/16/2023 6:18 PM.
