[olddog]

From my research to build my spread sheet (which is not complete), the 351W, 351C, 351M, and 400M are the only Ford pushrod engines to use the odd firing order. I didn't check the old "Y" block.

Interestingly I saw a TV show where they used a different firing order on a SB Chevy. They claimed it created a better scavenging affect and increased about 50 hp (don't trust my memory on that number). They ran it on a dyno with a regular cam of the same duration and lift. It changed more than just the 5,4 / 3,7 swap of the Ford engines. Anyone ever seen anything like this on a Ford?