Below is the technical data on the 1954 261 in 1954 Engineering Features book - it provides a comparison of hp and torque among 1953 Thriftmaster and 1954 Thriftmaster, Loadmaster, and Jobmaster engines.
1953 and 1954 235 Thriftmaster engines:
[img]http://ares.cs.siena.edu/~lederman/truck/Photos/2355354torquehp.JPG[/img]
1954 Loadmaster 235 & Jobmaster 261 engines:
[img]http://ares.cs.siena.edu/~lederman/truck/Photos/261235torquehp.JPG[/img]
The percentage improvement between 1954 and earlier engines is greater than the percentage difference between 1954 235 and 261 engines.
Nonetheless, my 261 was noticeably more powerful (low and high end) than the 235 it replaced (even before the 261 was "hopped" up). My 261 is a 1960 model from a large school bus and the torque/hp ratings most likely improved in comparison to the 1954 261.
JD54, You commented about 235 external parts fitting the 261 engine. Besides water pumps and thermostat housings being different but interchangeable (within same years - I think there was a change in 55/56 in both 235/261 engines), the only major external-part difference is the '58-'62 261 has a completely different oil filtering system (not interchangeable with the 235). I think the Canadian 261 has the same oil filtering system as the 235 (for all years).
The flywheel/starter changed with the switchover to 12v in both the 235/261.
Tim
