Guys need help, I was sold a 455 and paid a pretty penny for it. It has the F code on the water pump shelf which so.ewhat means 68-72. Oil tube number starts with a 3, number stamp on front left driver's block tab starts with 33M, number embossed on block by distributor is 8 - 160...... it has J heads I was told it was a 68-72 455 with 500ft lbs of torque and the J heads weren't orig to the motor. The entire number on the tab in the front left of the motor is 33M511821 can anyone help please..... my research say I have a 1973 455 which was rated at 225hp 8.5:1 compression and 360ft lbs of torgue??? I wanted this 455 to go in my 68 442 turnpike cruiser but my 290hp 2bbl w C heads might have more power??

 

Yes, that is a 1973 engine that came with J heads.

You could just put a 4bbl intake and carburetor on the 290hp 2bbl w C heads. if you want a year correct engine.

Keep in mind that you can't really compare the early (1970-older) SAE GROSS ratings with the later (1971-newer) SAE NET ratings.
For instance, the 350-4bbl engine in my 1971 Cutlass was rated both ways, with 200 HP NET, but 260 HP GROSS, and in my personal experience had almost exactly the same performance (acceleration) as my 1970 350-4bbl that was rated 310 HP GROSS. I always found it very hard to believe there was a 50 HP difference due to 8.5:1 compression and 10.25:1 compression.

 

Make sure you're not comparing net horsepower to gross horsepower. That was right about when they started changing how the power was reported.

 

See Post #2