I bought a used 87 mustang with a carbureted 351w about a year ago, haven't been able to work on it for a while. I have finally been getting into it and am having a misfire issue with cylinder 1. I am not sure where the block came from but it is rebuilt with hypereutectic pistons, an unknown cam, decked gt40 heads and a Holley 670 Street avenger.
When i got the car the secondaries did not open, bad diaphragm so i rebuilt the carb and ever since rebuilding the carburetor i have been having issues getting it to run properly.
I checked the timing and its okay. I noticed that the seller had the firing order in this manner: 1-6-3-7-8-2-5-4.....I know that the firing order for the 351W should be: 1-3-7-2-6-5-4-8
When I changed the firing order to the correct one, the car didn't even start. I changed back to the initial firing order and it "fired" right up. But the misfire was still there. I pulled the wires one at a time and replaced them after I noticed if there was a change.
Using the 1-6-3-7-8-2-5-4 firing order the #1 plug wire is pulled the car idles fine. Any suggestions?
If I do have to check the distributor position what is the procedure to check if the distributor is 180 degrees off?
This is where I would start, identify the block to know exactly what you have and do go by what the seller say's he sold you.
Q. How do I tell the difference between a 302, a 351W, a 351C, and a 351M?
A. By using combinations of the following facts, you should be able to positively identify what engine you have.
The number of valve cover bolts per head
o FE = 5
o 351W = 6
o 351C = 8
o 351M = 8
o 335 series big blocks = 7
The thermostat housing location
o 351W has it on the intake manifold
o 351C has it on the block
Fuel pump mounting style
o 351W has bolts on each side of the fuel pump
o 351C has bolts on the top and bottom of the fuel pump
Water pump boss
o 302 water pump boss goes right up to the bottom of the head
o 351W water pump boss stops below the top of the block " about 1” below the bottom of the head
o 302 firing order is 1-5-4-2-6-3-7-8
o 351W and late 302 H.O. firing order is 1-3-7-2-6-5-4-8
o 351C has the dipstick going into the block
o 351M has the dipstick going into the oil pan
351W eighth digit in the engine ID number is generally an “H”