I just bought a 65 mustang and its got a 302HO in it with a miss that i've been trying to figure out. I hate when things like this happen because it seems like you just have to guess as to what the problem might be and you end up replacing a lot of stuff that you dont have to to fix the problem. Its a 87 302 with a F303 cam, air gap intake, holley 750 double pumper, world windsor jr heads, msd large cap distributor, msd wires, 6AL ignition, and NGK UR4 spark plugs. I pulled the plugs and they were the wrong kind for the heads, they were like a .700 reach plug where the heads need a .460 reach plug and I thought that would have fixed it, but it only runs a little better after I did that. I cleaned all the terminals in the dist cap and that also helped some but there is still a miss. I was thinking about getting new taylor plug wires next but the wires on it look like they are brand new and i think it would probably be a waste of money. What do you guys think I should do next?