You are correct that an engine with number ending in F54Y is a '54 235, originally designated for use in a Powerglide equipped car, manufactured in the Flint, MI plant. The rated HP was 125, as you found. The engine has hydraulic valve lifters, if still in the original configuration, and not changed over the years. There is nothing wrong with the '913 head design. The combustion chamber is slightly larger than the later 848 head, which, if my memory serves me correctly, drops the compression ratio about a quarter, maybe half, point. So, not much difference in performance compared to the later 235s, and your engine's performance will depend more on state of tune and mechanical condition from a practical standpoint.
That engine should serve you well. Compared to the later blocks, it uses the older style water pump, which can be a benefit, since it positions the fan higher behind the radiator in the correct position. The block will have side motor mount locations, but I'm guessing the front cover has already been modified to use the front mount truck configuration, or exchanged with an older front mount cover, either of which work fine.
Motor on!
Doug
Last edited by drdoug; 12/21/2020 12:05 AM.
