What is the rationale behind the 4 - 7 theory for the firing order. why do they say it runs better and what all do you have to do ( besides changing the plug wires) to make it sucessful?

thanks moports

There should be a bunch of ideas on this one. From what I know and I'm sure I'll be corrected here if I'm wrong, the differences are in pumping losses due to less crank deflection on the different crank throws. There are some builders who find power there, others who find smoothness within a certain rpm range. Some find nothing. I think a ton of the "found power" has to do with getting the precise cam to match the head and rpm combo. If that is not already perfect, I don't think you'll see a gain. Personally, I don't see much of a bonus in it and I never bothered. But, for some in certain circumstances due to class restrictions or whatever, they may find it helps. The only thing that needs to be changed is the cam from what I know. Which is arguably limited.

i believe you'll notice the motor sounds a little different

Ford changed teh firing order on the EFI 302/5.0 in the mid 80s. The HO Mustang engine has a different firing order than the standard EFI engine.

Although the order is different than Mopar, you might be able to research the reasons behind that design change, might get some insight...

i dont see the big deal.
its basic principal is the same as if you just turn the engine around ...other wise every thing else is the same.
how could that improve hp or anything else.?
cheapst.

David Reher stated that they did not do it for power, they thought reliability was better.

I have a buddy at work with a 565 Schmidt motor that he paid for the 4-7 swap on. Motor never made good power and was in fact a pig, until he put the 4 and 7 wires in the normal place on the cap. Schmidt hosed him.

the 4-7 and 2-3 swap is what you need to do

Ford had a better idea? Must be the reason those Ford motors run so darn good!

the 4/7 2/3 swap make the pulse order same as late ford & chevy, some gains to be found there, also better on the mains

The 4/7 swap gives you the old flathead Ford firing order. The 4/7 2/3 swap gives you the 351W firing order. Nothing really magical about either of those motors in terms of performance.

Anyone know what the firing order on the new 5.7 Hemi motors is?

I found this but Now I am confused. What up with the coil and then plug numbers?