i have a 1987 f250 custom with the 4 speed manual trans, and the 351 Windsor in it, i recently picked up and was running strong for about a week, after that it started to bog out going up even the slightest hill, i replaced the fuel filter, air filter, and exhaust system and it i still doing so up hills i don't know what else to do it seems as though it is just not receiving fuel going up hill? any suggestions would be appreciated.
Checking the fuel pressure and fuel output would be your next step.
If may be a bad fuel pump, clogged filter (fuel sock on fuel pickup tube on the sending unit inside the fuel tank).
It could also be clogged fuel injectors where a fuel injector cleaning should be performed. This should be done by a professional Mechanic.
A clogged Catalytic Converter can also give you the same symptoms. Performing a back pressure test on the exhaust system would be the next step.
Having the computer system scanned for any trouble codes would also be a good idea. If any are found they should be fixed before anything else is performed.
This could be just the beginning of your diagnostics
Try these suggestions and get back to me when you can. Good Luck.