You have to be kidding me!
 

I just bought my 67 mustang a month ago and have been going through it tuning it up. Today I just realized that the firing order has been completely wrong! The guy before me was an idiot:icon_doh:! What kind of effects has that been having on the car? Can I just change the wires to the right firing order and be good? Any advice would help. Thanks.

I would have just run crappy.

Is it a 302? I believe there are different firing orders for 302's. You should have noticed it really running crappy and perhaps a backfire or two.

effects: running slower, worse gas mileage, and possibly long term damage.

Just change the wires back and see how she runs

That's really not THAT surprising. Not for a 67 anything. There are a lot of home "master" mechanics. Just fix it right, it'll probably be fine.

Not an old 302, they have the same firing order as a 289 which is 1-5-4-2-6-3-7-8

Newer 302s have the same firing order as old 351s, it is 1-3-7-2-6-5-4-8

It is in fact a 289...I even saw the firing order on the engine block as I was cleaning it today. Thanks for the responses!

Just out of curiousity, how are you measuring the firing order? Find #1 and check ccw around the cap?

Well, I rewired it according to the 289 specs and the car wont start! Now what do I do? I dont remember the old config. Any ideas? Could the firing order been changed? Why would the be the case?

You need to find top dead center on #1 In other words both valves need to be close and the timing mark on the balancer needs to be at 0. Then you wire it up with #1 being wherever the rotor is pointing and go from there. This pic might help. So it was running before but the PO didnt do something right?

http://i189.photobucket.com/albums/z...iringorder.jpg