What is the difference in mechanical fuel pump for a 1965 ford 289 CID and 1967 block?

The main difference between mechanical fuel pumps for a 1965 and a 1967 Ford 289 CID engine lies in the mounting flange. While the internal workings might be very similar or even identical depending on the specific pump supplier (Ford used various suppliers over the years), the way the pump bolts to the engine block changed slightly between model years. This is due to subtle variations in the block casting itself.

You will *not* be able to directly swap a 1965 fuel pump onto a 1967 block (or vice versa) without potential fitment issues. The bolt holes may not align correctly, leading to leaks or the pump not being able to be securely mounted. You'll need a fuel pump specific to the year of the engine block.

It's important to note that "1965 block" and "1967 block" are very general terms. There could have been minor variations within those years as well, impacting the fuel pump compatibility. Always double-check the specific casting numbers on your engine block to ensure accurate parts identification. A reputable parts supplier will be able to help you identify the correct pump based on these numbers.