[olddog]

The 15426378 firing order was used by the FE, and 385 series engines, in addition to the SB Ford. The 351 W and 351 C (and 400) used the 13726548 firing order.

If you sit down and draw out the firing order and then re-number the cylinders as Chevy and Mopar numbered them, you will discover that they also used the 15426378 firing order. The difference is that they numbered the cylinders differently.

I saw the show Bill37341 mentioned on the SB Chevy. I didn't catch the firing order and was not able to confirm it was the same as the 351 Ford. I was thinking they only swapped 2 cylinders and the 351 swaps 4. I wish I could find this out for certain. They did prove the other firing order made more Hp. Memory is somewhere between 5 and 30, but I'm thinking around 10 hp. They said it was do to air flow improvement in the intake manifold, by changing the order the flow hops from port to port. It would also change flow pulses in the exhaust.