I have a 58 F100 with a 223 I beleive is out of a later 63or 64 ford. Anyways,, I was driving the other day and had the engine running down the road at a moderatly high RPM (65mph) and when I pulled into town I noticed alittle noise that sounded like a loud tapit,, very quiet though,, almost couldn't even make it out but ran fine. I went to where I was going and parked it for acouple hours then came back out started it up and it ran fine except for that very quiet tapit like sound. I pulled up to the pizza place to pick up a to go pizza and left the pickup run while I ran in. I came back out 5-8min later and it was running fine. I pulled out onto the street and started to accelerate normally and it started to miss, pop, bang, backfire. I didn't loose oil pressure. When coasting it didn't do anything but miss on 1 or 2 cylinders but when accelerating it would miss, pop, bang and backfire. I wasn't too far from home so I nursed it home. She never heated, never lossed oil pressure and wasn't leaking any fluid. Upon getting home I parked her and checked the oil, there was no water in oil. Starts but missing on 1-2 cylinders which I think are either cylinder 3 or 4 due to wet plugs on those cylinders. I pulled head cover and all push rods, arm and springs are workin properly. Has new plugs, wires, cap, rotor, electronic ignition and coil so I don't think its electrical. The next step is to do a compression test on the cylinders. Does anyone have any advise or thoughts that could help me? It would be greatly appreciated!