360 or 390 question
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Posting Guru
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From: Lockport, NY
360 or 390 question
OK I just bought this 76 F250 4x4 XLT Highboy, I was told by the previous owner who had bought it to restore but didn't, that it has a 390 in it, the 4th digit in the vin is Y so that indicates 360, and I was told that 4x4's did not come with 390's, it has a stock looking 4bbl manifold with a Holley carb on it, it runs good and strong, has good oil pressure, and has a bit of a lope to it like someone may have put a cam in it? so what I am looking for is info on the 360 and 390, obviously someone has done some work here, how hard is it to determine what motor this is? I just want to know what I got here so in the future when I go to get parts I get the right ones! Thanks .Salt-Man 
Post Fiend
Joined: Mar 2004
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From: Union, Washington
After this many years, only God and the guy that swapped the engine would know. Check the stroke to see whether it's a 360 or a 390 (that's the difference). 360 is a 3.50" stroke and a 390 is 3.78". Pull the plugs and sets the engine timing marks to TDC. Put a dowel into plug hole and mark the dowel. Turn the motor over 360° by hand to TDC again and measure the dowel again. Then measure between the marks and have you answer. The stock manifold and Holley 4 barrel only mean they are off an FE. No 360s came with a 4V. Some 390s did but that means nothing because most light truck engines were 2Vs.
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Posting Guru
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From: Lockport, NY
Thanks for that measurement deal I will do that, that is a easy enough way to determine what I got.
do the 360's and 390's share the same block and bore? and it is just the stroke that is different between them?
if so then it could still be a 360 with a 390's 4v manifold? yes or no
are there any numbers I can look for? just wondering?
do the 360's and 390's share the same block and bore? and it is just the stroke that is different between them?
if so then it could still be a 360 with a 390's 4v manifold? yes or no
are there any numbers I can look for? just wondering?
Post Fiend
Joined: Mar 2004
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From: Union, Washington
Same block and bore, 4.05", the same heads, intakes, etc all except crank, rods and sometimes pistons. Yes the 4V manifolds off 390s, 428s, etc will fit the 360. Look for numbers on the manifold (also look for and "S" on one of the front runners) and heads (between the two center sparkers). Look for a tag on under the dist. hold down if it's still there. Numbers on the carb air horn or off the tag on the carb it is still there.
Hotshot
Joined: May 2003
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From: south louisiana
Some Ford's got Holleys, but in a pickup? Not likely. A look at the list number on the choke horn front will tell you what Holley it is. Post the list number here and someone can tell you which Holley you've got.
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Post Fiend
Joined: Mar 2004
Posts: 6,056
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From: Union, Washington
Originally Posted by baddad457
Some Ford's got Holleys, but in a pickup? Not likely. A look at the list number on the choke horn front will tell you what Holley it is. Post the list number here and someone can tell you which Holley you've got.
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Cargo Master
Joined: Aug 2000
Posts: 2,931
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From: SW Michigan
nice old truck
66salt, thats a nice looking find you have there. It is almost certain that the truck came with a 360 and a 2 barrel carb. That was normal for the 4wds. But it was made thirty years ago, lots of things can happen. When I bought ( in 1981 ? ) my '71 F100 4wd, it had the correct rear sump oilpan, but a 390 with flattops and an aluminum police interceptor intake with a holley 750 on top. It looked VERY factory. In 1975 & 6, many of the 390s in the 2wd trucks came with a cast iron 4V intake and a Holley 600 with special boosters. What kind of boosters are in your carb ? I would suspect your truck, like mine, has the benefit of some creative swapping of factory parts. You'll need a piece of wooden dowel to check the stroke. tags and casting numbers don't mean anything in your case. We don't know what parts were used, and tags could be missing or changed. The only parts differant from the 390 and 360 are the crank, rods, and pistons- and the 360 actually uses an old 390 flattop piston design. Lucky you. DF, on his son's computer
Cargo Master
Joined: Aug 2000
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From: SW Michigan
healthy old truck
Salt, what are you looking to get started on ? It looks like you're ready go right now. Is there anything that would prevent you from driving and enjoying it right now, just like it is ? If you're looking to modify, headers should be first on your list, because the stock FE exhaust manifolds are SO bad. DF
Postmaster
Joined: Jul 2005
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Nice score on the truck, looks sharp, any picture of the FE engine.
Measure the stroke by removing the spark plug and measuring the stroke by turning the crankshaft from TDC.
Off the subject, I will be scoring a 1977 F250 Hi boy soon.
Measure the stroke by removing the spark plug and measuring the stroke by turning the crankshaft from TDC.
Off the subject, I will be scoring a 1977 F250 Hi boy soon.
Last edited by 1975Ford; Jan 10, 2008 at 09:11 AM.