'87 Ford F150 won't start

I just put an '86 5.0 engine from an F150 2wd pickup in my '87 truck of the same model. The motor was running when pulled but when I set in the '87, it won’t run. I’ve replaced coil, distributor assembly, plugs, wires, throttle body, checked timing etc. I’ve got spark through the plugs and fuel in the cylinder but with no luck. Don’t know where to turn next. Please help! Thanks.

Check the ground wire between the cylinder head and the firewall to make sure it’s clean and tight.


Are you certain that the distributor is correctly timed?

Thanks for the replies. And we found the problem. Seems as we were checking ground wires, we found that the ground coming down from the battery was not hooked to anything but dangling close enough to the block to let the motor turn over but not start. Fixed the problem and she runs like a champ. Thanks again.