77 F-250 Custom engine
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77 F-250 Custom engine
I'm new to the site and need desperate help. I have a 1977 F-250 Custom im trying to fix up. There is a chance at some point there was an engine overhaul or engine swap. By vin number it should have a 351M, but I have also been told it could be a 400 or 460. I've found these cast numbers if someone can help me figure it out. D7TE-9C485-DHA AND D5AB-8401-AB both found on the side of the same side of the engine.
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Unfortunately I believe it's a 335 series engine and that's a bummer. if it's a 2v carb it's not a 460 all 460's were 4v and all 351's and 400's were 2v. obviously someone could put a 4v on a 335 series though.
There are other ways to tell but a 2v is a dead give away for a simple identification.
There are other ways to tell but a 2v is a dead give away for a simple identification.
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429/460 = 7 bolts to hold on the valve cover
351m/400 = 8 bolts to hold on the valve cover
Those casting numbers are close to those for 351M/400s,, but not an exact match to anything I can find.
It's probably the original 351M.
351m/400 = 8 bolts to hold on the valve cover
Those casting numbers are close to those for 351M/400s,, but not an exact match to anything I can find.
It's probably the original 351M.
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If it has 8 valve cover bolts, it's probably the OEM 351M.
Externally, the 351M and 400 are identical. Crank and pistons are the only difference. It's difficult to check the stroke via the wire down the spark plug hole method, but if you are careful, you may be able to get a measurement.
You say you are trying to fix it up. OK, does it run?
If it runs, does it run good? If yes, tune it up, fresh oil and drive it.
If it doesn't run, try to figure out what's wrong and then decide if you're going to rebuild it. If you have to rebuild it, make it a 400.
More power is almost always a good thing, but even with the limited power of the 351M, BILLIONS of miles were racked up by 351M powered vehicles.
Externally, the 351M and 400 are identical. Crank and pistons are the only difference. It's difficult to check the stroke via the wire down the spark plug hole method, but if you are careful, you may be able to get a measurement.
You say you are trying to fix it up. OK, does it run?
If it runs, does it run good? If yes, tune it up, fresh oil and drive it.
If it doesn't run, try to figure out what's wrong and then decide if you're going to rebuild it. If you have to rebuild it, make it a 400.
More power is almost always a good thing, but even with the limited power of the 351M, BILLIONS of miles were racked up by 351M powered vehicles.
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