[Tom Vaught]

On Marty's Turbo Engine we looked at doing a Ford 351 firing order as that took the double firing hit (Number 2 and then Number 1) off the front main. This was a durability fix that Ford has used for years. The Ford 302 firing order is EXACTLY the same as the GM numbering EXCEPT that Ford numbers the cylinders differently vs GM.

Reher/Morrison did a lot of testing with the different firing orders and found that doing the 4/7 swap eliminated some of the heat in the back of the block from the 5/7 firing deal. The 4/7 deal still has the two front passenger side cylinders firing next to each other 4 then 2 and you still have the 2 then 1 front main double hit BUT the water pump discharge is much closer to the 2 and 4 cylinders so the double hit is cooled much better with the 4/7 swap.

Making power is based on looking at the whole system and trying to find the best compromised for best durability and power.

With a Belt Driven Supercharger there might be increased gain in durability of the crank with doing the 351 Ford firing order. With a NA engine the best combo might be the 4/7 swap. For a typical street strip deal the cost of the parts might not warrant the change. (Specially ground camshaft).

Everyones unique decision.

Tom V.