Regarding Firing Order

[jaybee]

Being a lazy Sunday morning I found myself wondering why the difference between Ford 260/289/302/FE/Lima big block firing order and the 351 firing order. The 351 firing order is also used on 5.0 HO engines and Ford eventually switched to the 351 firing order in all 5.0 engines. When you adjust for cylinder numbering conventions the 351 firing order also matches the LS and sbc 4-7, 2-3 swap. The Flathead, Coyote, and sbc 4-7 swaps are also a match.

If anyone is interested, here's a link. Bottom line...in a near-stock application it probably doesn't make a bit of difference. In an engine that's built to really scream the 351 and Coyote firing orders can exhibit marginal improvements in crank vibration and rear cylinder cooling. https://www.enginelabs.com/engine-tech/engine/firing-order-swaps-whats-best-for-your-engine/

[chimp koose]

I have heard that the 4-7 swap is good for blower motors . better crank life . No experience , just what i have read. Worth a few hp on big hp engines .

[enjenjo]

If you number the Ford cylinders like GM does, the 351 firing order is the same as a 350 Chevy. My thought on the alternate firing order was that Ford used it to ge a distinctive sound. I can tell a 5.o from a Chevy from a mile away.

[kb426]

I had a discussion with a Ford tech a decade ago about the engine sound. He told me that he didn't think the firing order had anything to do with it. I have no back to back exp. to dispute why they sound different, they just do. Maybe it's a combination of intake manifold and cylinder head design. I have seen that there are similar cam grinds for chevys and sbf's. ??

[jaybee]

I like that they brought flat plane cranks into the discussion, too. I took another side trip at the mention of exhaust-generated downforce in Top Fuel cars. It's very significant at 900-1100 lbs!