Hey folks, love this site, it has a wealth of information. I tried to do a search for answers but came up with nothing. Hope someone can help, I'm stumped.

I have a '95 F150 4x4 with mass-air 302 and auto o/d, I bought the truck with no compression in no.1 cylinder. It ran and drove, but had a miss to it. Got it home and pulled the heads to reveal a chunk missing out of the no.1 piston. Not quite as easy of a fix as I hoped.
I found a low mileage Jasper 302 in a '89 F150 2wd that ran good and I drove it home. I pulled the motor out and put new gaskets and oil pump on it. I then installed it into the '95, just the long block though. I re-used the '95 distributer, intakes, exhaust manifolds, and injection. I also put on new plugs, wires, cap & rotor. Seemed simple enough, it was done in a days time, but it wouldn't run in the '95. It had spark, had fuel to the rail, but the injectors weren't squirting. I then swapped them out for the '89 injectors since they appeared the same, and they squirted. Back together it went and fired right up, but it ran very rough. I then checked the timing, it was on. It runs too crappy to drive. It will idle alright, but has a slight miss. As soon as you give it gas, it backfires and stumbles even more. So here it sits and I am stumped.
Will this older 302 not work in this newer truck? The '95 injectors sat for a while so I think that is why they wouldn't work. Should I have them cleaned and checked and put them in? Will the '89 injectors work, so it must be a timing issue? Any help would be appreciated.

 

The 89 motor uses the early Ford firing order (15426378) Your 95 had a different cam (F4TE roller) with the 13726548 F/O) Wire the distributor cap for the earlier F/O then try it. The 89 will probably run rich too, the F4TE cam is mucho healthier than the 89's cam. The F4TE cam is a step below the GT/HO cam.

 

Thank you, I tried the '89 firing order and the motor wouldn't run at all. So, I changed it back to the '95 and it will run again, but still rough like before. I'm thinking maybe it has to do with the injectors, since they are from the '89?

 

Yea, the injectors I guess are sequential firing and not batch fire, that's probably why it wouldn't run at all. I'm not sure about the workings of the EFI system but I know for a fact the cam firing order is different between an 89 cam and the 94's F4TE roller. If you cannot rewire the injectors only way to go would be a cam swap to a 351W flat tappet or swap the F4TE cam into the 89 block. The 89 block should be a roller block so that's not an issue. The cam swap will be a plus over the 89's grind.