Thread: How to tell what firing order

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302/351/5.0/5.8 -

Now that you are confused, let me just add one more thud to your day - it could just be a reverse rotation motor These are often used in boats.

221 - 302 = 1-5-4-2-6-3-7-8
351W(all) & 5.0 H.O. and late 5.0 non H.O. = 1-3-7-2-6-5-4-8

Here's the info for a marine engine: http://www.basicpower.com/firingorder.htm
If memory serves me correctly, but not positive, these reverse rotation engines may be cylinder numbered from the transmission end!!!

Then to make life even more fun, RR motors have different camshafts, distributor drives and water pumps. Other then that - about identical to standard rotation

Having fun yet!!!

Most single engine configuration boats are standard rotation..If that makes you feel better..

Pull the valve cover and turn it until #1 intake opens. Keep turning and watch which one opens next. If it's #5, then it's 15486372. If it's #3, it's the other one.

Originally Posted by R Pope

Pull the valve cover and turn it until #1 intake opens. Keep turning and watch which one opens next. If it's #5, then it's 15486372. If it's #3, it's the other one.

That's a great tip Ron. Logical, but unless you stop to think about it this would never dawn on you. I've filed that one away.

Don