Assuming it is actually an '85 HO with the roller cam, 1-3-7-2-6-5-4-8
Edit: Any of the 351W that I have encountered used the same firing order as the 5.0 HO. Perhaps they also made some with the same firing order as the older 302's. I found this link on summit racing to use as a general reference.
the car was running with the non ho firing order of 15426378...but there was a miss at 3500 RPMs, could that be because the firing order is wrong because i have no idea if this is the original motor in this car or not?
If the firing order on the cap were wrong - look at the two sequences - it would only be running on 4 cylinders (1,2,6 and 8) - it'd barely run, not just have a miss at 3500. The 85 HO has the same firing order as other HO's (same cam from 85-88); it's the one listed above - 1-3-7-2-6-5-4-8. The 351W has the non-HO firing order - 1-5-4-2-6-3-7-8. Sounds like the 302 in your 85 is a non-HO.
well rite now its only running on 4 cylinders....but before it felt fine..a friend of mine disconnected the vaccuum advance, i drove it, still drove like crap, plugged it back in and now its still running horrible.
You need to know which engine you have. If its the roller 5.0 then its the same as any roller 5.0 from 85 to 95. I have a carbed 85 and it used to have the original 85 roller 5.0 HO engine in it and it ran with the standard 5.0 timing order.
Matt - I was just going by the info in your post - you described the problem as "there was a miss at 3500 RPMs" - not how I would've thought running on 4 cylinders would be described. Running on 4 it will be missing on at least 4 cylinders at all rpm.
You've got both firing orders -- try the 1-3 and the 1-5 orders; if it's firing order related one of those will clear it up. If it runs ok on the 1-3 it's got an HO cam. If it runs ok on the 1-5, then all that can be concluded is that it does not have an HO cam in it. Whether or not it's the original motor will take more investigation.
well i checked it this morning. The spark plug arrangement IS 1-3-7-2-6-5-4-8 The car decided its not missing at thru out the rpm range, just at 3500 rpms again. Changed the order to non h.o. and it would barely run, so I have the wires on the 1-3-7-2-6-5-4-8 and it ran with the small miss. Maybe I had a loose wire???? I'm gonna check and re-do the plugs again. What's the firing order for the plugs? Thanks everyone for your responses.
FoxChassis - I think I may have unintentionally misled with my earlier post - trying to learn here. You data shows the 351W and the HO302 with the same firing order - is that right? I was under the impression that the HO302 was stand alone with it's firing order, and all the rest, including the 351W had the 1-7 firing order.