Do all stock ford 5.0 roller cams have the 351 (13726548) firring order, or did some have the old 302 firring order (15426378)
could be either one. MOST of the HO firing orders are 1-3-7-2-6-5-4-8. Some of the early HO engines were 1-5-4-2-6-3-7-8. Early being '85-'87, IIRC.
Generally speaking, and with very few exceptions that I know of, HOs got the W firing order, while non-HOs got the old firing order. I don't know of any HO with the old FO, but some others might know better. I am not as well informed on newer engines, except the fact that I have a truck with a non-HO replacement roller engine, so I know that non-HOs have old FO.
All the HO cams had the 351 F/O. No exceptions. All the non HO roller cams, except the 94--2001 F4TE cam had the old 302 F/O. The Cobra roller cam also had the 351 F/O. There were basically 4 different stock roller cams----the "base" roller(86-91 full size Ford, Merc & Lincoln plus the 86-92 T-Bird/Cougar & 91-93 pickups and vans), the HO roller, the Cobra roller(also used in 93 only in the T-Bird/Cougar) and the F4TE roller(all 94-97 5.0 & roller cammed 5.8's plus all the Exploder/Mountaineer 5.0's). There were several minor revisions done to the HO roller, but changing the F/O wasn't one.
http://www.moddedmustangs.com/reference/firing-orders.php I originally had my order set for the old 302 in a 95 5.0, didn't work so hot, but it did run on 4 cyl
I prefer the 1 5 4 2 6 3 7 8 firing order... whether it is correct or not. lol Most aftermarket cams use the 1 5 4 2 6 3 7 8 firing order however, so if it isnt a stocker, who knows.
There is an engineering reason for using the W FO. It places less stress on the crank and main webbing. Has something to do with cylinders on the same journal firing consecutively on the 302 FO, the 351 FO spreads the load on the crank more evenly. Don't remember the details, but that is the reason for the HO using it. If you impose the other's cylinder numbering on the engine, the 302 and SBC use the same FO. When Ford started using the W FO on the HOs, the SBC guys noticed and started experimenting. Comp now makes a whole line of SBC cams on the 351 FO. They say the cams with that FO on the SBC are proven to make an extra 15hp while adding durability to the short block. All has to do with making the load on the crank even. Just a thought. I went with a W cam for that reason in my 302. I have no way to prove it makes more power or is more durable. I am just following the trend.
Yea.. I've heard that also. Why alot of Chevrolet guys brag about having a "special" firing order cam, when in all actuality it's just a FORD cam
My thoughts are if it really works on a SBC, then it should do the same on a SBF. They have the same FO standard... So the 351 FO should have the exact same effect.
