Thanks! Very interesting...as we know the 261 has a bit more torque than the 235 but compare the gross torque lines. The high torque 235 hits peak torque faster and maintains that level longer through the rpm range. Of course that 261 has a slightly lower compression ratio. I've never been certain where the extra .25 came from on the 235. Probably Jerry knows.
'56 and later 235s came with a 848 head. The 261 did not. I am guessing the combustion chambers are larger in the 261 head, thus lowering the compression ratio. These engines were designed for big trucks which were run at max RPM frequently. A compression ratio higher than 8.0 to 1 is probably not conducive to engine longevity under those extreme conditions with that engine.
My 2 cents, refundable upon request. Just submit a bank account number for deposit purposes. Please also include full name, date of birth, and the last 9 digits of your SSN.
Carl
