Q&A

Mailbag: Why Did Ford Change the Firing Order on the 5.0L 302 H.O. Engine?

 
Ford 5.0L HO

(Image/forums.nasioc.com – B6lovin)

Q: I’m building a Ford 302 engine, and I’m looking at camshafts. I’m curious—why did Ford change the firing order on the 5.0L (302) HO engine?

A: This question gets a lot of mileage on internet forums, and there’s no shortage of speculation on the subject.

According to Ford Motor Co. engineers, the 5.0L H.O. adopted the 351W firing order (1-3-7-2-6-5-4-8) to improve the intake manifold sound quality. Ford’s 5.0L H.O. has a distinct sound that benefits greatly from the addition of a cold air intake system and a pair of chambered mufflers.

Check out the V8 firing order chart and see how the 302 and 5.0L H.O. (listed below as the “5.0L EFI”) compare.

Common Engine Firing Orders

This is another in a series of weekly Q&A Mailbag sessions with Summit Racing‘s tech department, in which there are hundreds more. Click here to see them all.

 

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4 Comments

  1. Okay…let’s go back in time a bit and ask “Why did Ford change its long-established V8 firing order with the introduction of the 351W in ’69? It certainly WASN’T for “intake manifold sound quality”. The 385-series, which predates the 351W retains the “old” firing order while the 335-series, the HO and the Modular use the “new” firing order. Seems like there has to be ANOTHER reason….

  2. It’s an upgrade, keeping cylinders 7 and 8 from firing consecutively. Also they had a windsor camshaft that had the specs they wanted, so to save money.

  3. Terry Zeissler says:

    The revised firing order was needed to prevent inductive crossfire burning a hole through the center of number four piston. This would happen under load if the spark plug wires were not routed correctly on the right bank. I had to deny warranty on many 302 engines that we remanufactured for this reason. Not a problem with the 351W no matter where you ran the plug wires.

    Terry Zeissler
    Technical Services Manager (Retired)
    Optimax Engine Reman (A NAPA Company)

  4. Pingback: Mailbag: Breathing Life Into a Wheelchair-Friendly 5.0L-Powered Ford E-150 Econoline - OnAllCylinders

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