351w firing order(s) !!

[mikepasquale1]

So i got the exhaust put on at the shop today. Lately i have been having a ton of timing issues and my car is just not hitting all 8 cylinders. After the exhaust was put on all of the mechanics dug into the issue. Alot of them were telling me that the firing order was incorrect and that they have seen this same issue before with others. After trying every last thing they changed the firing order.

heres what it was: 1-3-7-2-6-5-4-8

this is what they changed it to: 1-5-4-2-6-3-7-8

Ya, a firing order for a 302?????????

Turned the key and..........it ran perfectly fine!!!!!!!! no misses, fires on all 8, no back firing, and sounds amazing with the flowmaster 40's.

I dont get it, but i have heard before from a few different Ford junkies that there were 2 different firing orders for a few years for the 351w. The motor in my car came out of an LTD i believe. Its a D2 date code.

Anyone else ever hear of this?

 

[73vertproject]

Mike -

I can't remember. Did you put a new motor in, or just rebuild the one that was there?

 

[mikepasquale1]

This was rebuilt for me at a local shop a few years ago. It came to me as a long block. I added intake, distributor, carb, etc. This motor was in a 70 mustang coupe that i had from a project car from a few years ago that was at the time, intended for that car.

 

[Flatback72]

This happened to me twenty years ago on my 1970 Mach 1. Decided the 351W was a bit tired and bought a reco short block changeover - put it all together and it started but was running like a bag of crap. Two hours it took before my mechanic brother discovered that the engine block supplier had put a 302W cam in it that altered the timing of four of the cylinders. Apparently it's not an abnormal practice to use the 302 cam, but very annoyed that they didn't bother to forewarn me.

 

[mikepasquale1]

Hmmm maybe thats whats going in with mine

 

[Totalled]

They put a 302 cam in it. The 351s had the other firing order.

 

[hyena429]

They put a 302 cam in it. The 351s had the other firing order.

Yup...I bet thats what happend...Some years could have a diffrent firing order "but its rare"......Now in chevy ...we ran into this rebuilding my cousins 327...You think the same block and fire order as a 350 huh? But we could even get it too pop...Well this old guy comes over and say..You know if its a real 327 the firing order will be completely back words? We like...Nooo..never heard of it....We put the firing order completely back words and the motor fired right up!!! He was sooo right..lol..Sounds like thou they put a 302 cam in yours.

 

[Flatback72]

From what I've read on the interweb the reason Ford changed the firing sequence for the 351W's was because the Ford engineers reckoned the new firing order put less stress on the bottom end. For what it's worth my 351 ran perfectly with the 302 cam in until the day I sold it 5 years later.

 

[mikepasquale1]

This happened to me twenty years ago on my 1970 Mach 1. Decided the 351W was a bit tired and bought a reco short block changeover - put it all together and it started but was running like a bag of crap. Two hours it took before my mechanic brother discovered that the engine block supplier had put a 302W cam in it that altered the timing of four of the cylinders. Apparently it's not an abnormal practice to use the 302 cam, but very annoyed that they didn't bother to forewarn me.

Ya we actually figured out that it was missing on 4 of the cylinders as well