F100?
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Joined: Apr 2009
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From: Stanley, VA
The difference is a '74 F150 doesn't exist.The F150 wasn't brought out untill 1975.
It was an emissions thing. The F150 had a higher GVW than the F100. This was to get around the requirement for catalytic converters and unleaded fuel.
It was an emissions thing. The F150 had a higher GVW than the F100. This was to get around the requirement for catalytic converters and unleaded fuel.
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Joined: Nov 2008
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From: Halifx Pa
GVW Gross Vehicle Weight, and yes back in the day there was regular, and unleaded gas. If you ran regular gas it was to cause some issues with the cat converter.
Look at a fuel inlet on today's vehicles, then look at the fuel hole in our dents, which is a much bigger hole. The regular gas nozzle would not fit into the unleaded vehicle, but the unleaded would, or does fit into the regular tanks fill hole.
Look at a fuel inlet on today's vehicles, then look at the fuel hole in our dents, which is a much bigger hole. The regular gas nozzle would not fit into the unleaded vehicle, but the unleaded would, or does fit into the regular tanks fill hole.
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Only way to verify is to measure the stroke thru the spark plug hole.
Nothing to be embarrassed by, a lot of 360s instantly become 390s on For Sale day.
Josh
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Fleet Mechanic
Joined: Jun 2007
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From: Ohio
the owner says it's a 390 and not the 360 so we'll see. he also said he refreshed it up last summer so i guess it could have been swapped then. but again i guess it'd take unleaded so thats good
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From: Western N.C.
Whether it has been "refreshed" or not, it can burn unleaded gas. However, without knowing for sure whether it has had hardened valve seats installed, you run the risk of burning them up.
Measure the stroke. Don't take anyone's word for it. That has been a deal breaker for me. Junkyard rustbucket '75 F250 4x4 with 106000 miles, wrecked (rolled) with a good running FE. The yard owner swore up and down that it was a 390, and would take no less than $500 for it. I told him if he would let me measure the stroke and it indeed had a stroke of 3.78 inches, I'd buy the motor on the spot for his price...$500...cash money, no haggling, no more questions asked. If it had a stroke of 3.50 inches (thus, a 360) I could buy it for half his price.
He said no deal....he suddenly wasn't sure...now that he thought of it, it could be a 360...though if it was, the guy he bought it from had slickered him. But he would let me have it for only $400.
I said no deal too. That's one more junkyard off the Rolodex, but no big loss. To me, that kind of crap is intolerable.
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Joined: Mar 2009
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From: Huntington WV
You said the 74 F100 ran on regular an the 75 F150 ran on unleaded gas. Would a 74 F250 run on regular as well when it was built in may 6, 74? An how can you check an see if the valve seats have been changed out an how hard is it to change them out?
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Fleet Mechanic
Joined: Jun 2007
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From: Ohio
See if he can more clearly define "refreshed it up." For some, that means changing the oil for the first time in five years.
Whether it has been "refreshed" or not, it can burn unleaded gas. However, without knowing for sure whether it has had hardened valve seats installed, you run the risk of burning them up.
Measure the stroke. Don't take anyone's word for it. That has been a deal breaker for me. Junkyard rustbucket '75 F250 4x4 with 106000 miles, wrecked (rolled) with a good running FE. The yard owner swore up and down that it was a 390, and would take no less than $500 for it. I told him if he would let me measure the stroke and it indeed had a stroke of 3.78 inches, I'd buy the motor on the spot for his price...$500...cash money, no haggling, no more questions asked. If it had a stroke of 3.50 inches (thus, a 360) I could buy it for half his price.
He said no deal....he suddenly wasn't sure...now that he thought of it, it could be a 360...though if it was, the guy he bought it from had slickered him. But he would let me have it for only $400.
I said no deal too. That's one more junkyard off the Rolodex, but no big loss. To me, that kind of crap is intolerable.
Whether it has been "refreshed" or not, it can burn unleaded gas. However, without knowing for sure whether it has had hardened valve seats installed, you run the risk of burning them up.
Measure the stroke. Don't take anyone's word for it. That has been a deal breaker for me. Junkyard rustbucket '75 F250 4x4 with 106000 miles, wrecked (rolled) with a good running FE. The yard owner swore up and down that it was a 390, and would take no less than $500 for it. I told him if he would let me measure the stroke and it indeed had a stroke of 3.78 inches, I'd buy the motor on the spot for his price...$500...cash money, no haggling, no more questions asked. If it had a stroke of 3.50 inches (thus, a 360) I could buy it for half his price.
He said no deal....he suddenly wasn't sure...now that he thought of it, it could be a 360...though if it was, the guy he bought it from had slickered him. But he would let me have it for only $400.
I said no deal too. That's one more junkyard off the Rolodex, but no big loss. To me, that kind of crap is intolerable.
This is what the guy said: "I just refreshed the 390 motor last summer. Its a real 390 (not a 360 someones trying to call a 390). 4X4 works good. It has a new starter, new lifters, new distributor, all new motor gaskets" so i don't know. it's not too big of a deal to me, the biggest part would just be to find out if it runs on unleaded. yes i want a 390, considering i just drove a highboy with one last week and that wasa an experience
, but hey to me a v8 is a v8, and if it's from the late 60s-early 70s, its a REAL v8. ha
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Joined: Apr 2009
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From: Stanley, VA
If it was built to run unleaded fuel the fuel fill pipe would have the restrictor built into it and the fuel gauge would say "unleaed fuel". A '74 F250 will more than likely be leaded regular.
You can only tell if it has hardened seats installed by pulling the heads and look to see if it has had them installed.
It's not that hard, any COMPETENT automotive machine shop can install hardened exhaust seats.
You can only tell if it has hardened seats installed by pulling the heads and look to see if it has had them installed.
It's not that hard, any COMPETENT automotive machine shop can install hardened exhaust seats.
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From: Mississippi
My 1976 owner's manual says that the F100 is designed to run on unleaded fuel only.It also states that F150 F250 and F350s are designed to run on regular (leaded) or low lead fuel. A side note: manual states that Canadian trucks may be operated on leaded or unleaded depending on the "engine application", "regular can be used unless the fuel gauge and filler states UNLEADED FUEL ONLY". My fillers do not have the restrictor in them either
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