HIGH BOY
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HIGH BOY
I HAVE A 74 3/4 TON 4 4 WITH A 390.MY FIRST QUESTON IS WHAT IS A HIGH BOY.MY SECOND QUESTON IS ABOUT THE 390,IT HAS A TAG ON THE SIDE OF THE BLOCK THAT IT HAS BEEN BORED 40 OVER.I BELIVE THIS TO BE A FACTORY TAG.IT ALSO HAS FACTORY CHROME VALVE COVERS AND 4 BARREL INTAKE.I KNOW THE 390 CAME OUT OF A EARLY 60 GALEXIE.I WOULD LIKE TO KNOW MORE ABOUT THIS MOTER,DID FORD MAKE THESE FOR A CERTON REASON,AND SINCE FORD BORED IT HOW MANY CUBES IS IT NOW. THANKS FOR ANY INFO
Fleet Owner
Joined: Jun 1999
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From: Creedmoor, North Carolina
HIGH BOY
Dog I don't think Ford bored that engine for new install. You might have a Ford reman. You could have a car engine installed, and the chrome could be aftermarket, or from another engine.
High Boy is a name picked up because the truck is so high off the ground. It is a street name, and is not official from Ford.
Hope this helps a little.
John
66 F100s
In the still cool hours of the night, you can hear chevys rusting away.
High Boy is a name picked up because the truck is so high off the ground. It is a street name, and is not official from Ford.
Hope this helps a little.
John
66 F100s
In the still cool hours of the night, you can hear chevys rusting away.
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HIGH BOY
Dog,
You can figure the current displacement with this simple(HA HA) formula:
calculate the current bore diameter by adding .04 inches to the original bore diameter. Divide this number by two, then square the quotient. Multiply this number by pi (3.1415927- of course, use only significant digits). Then multiply this product by the length of stroke. That will give you a volume displacement per cylinder. Multiply by 8 and voila! there is your current displacement.
the formula is: [(pi x radius)squared]x heighth
Nate
1964 F-100 Custom Cab 292 V-8 3 spd
1964 F-100 292 V-8 3 spd
1990 F-150 5.8L
You can figure the current displacement with this simple(HA HA) formula:
calculate the current bore diameter by adding .04 inches to the original bore diameter. Divide this number by two, then square the quotient. Multiply this number by pi (3.1415927- of course, use only significant digits). Then multiply this product by the length of stroke. That will give you a volume displacement per cylinder. Multiply by 8 and voila! there is your current displacement.
the formula is: [(pi x radius)squared]x heighth
Nate
1964 F-100 Custom Cab 292 V-8 3 spd
1964 F-100 292 V-8 3 spd
1990 F-150 5.8L
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Joined: Jan 2000
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HIGH BOY
My bad- you should not suare the radius until after you multiply it by pi.
so, it would be [(bore x pi)squared] x stroke
I'd figure it for you, but I don't know the bore and stroke on these engines.
Nate
1964 F-100 Custom Cab 292 V-8 3 spd
1964 F-100 292 V-8 3 spd
1990 F-150 5.8L
so, it would be [(bore x pi)squared] x stroke
I'd figure it for you, but I don't know the bore and stroke on these engines.
Nate
1964 F-100 Custom Cab 292 V-8 3 spd
1964 F-100 292 V-8 3 spd
1990 F-150 5.8L
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Joined: Jan 2000
Posts: 334
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HIGH BOY
Okay, I became obsessed with getting this right. The description I gave in post #2 is correct, but the formula is not. Post #3 is alltogether wrong, so disregard it.
Anyway, I found the specs and did the math. According to what I found, a 390 had a bore of 4.05 in and a 3.78 stroke. With it bored .040 over, you would increase displacement to 397 cubic inches.
Just wanted to clear it up, and apologize for the confusuion. Geometry was too long ago!
So, for one last time (to get it right)- figure displacement by squaring the radius of the bore, multiply that by pi (3.14), and then multiply the product by the stroke.
4.05 .040= 4.09
divide by 2 (to get radius)= 2.045
2.045 x 2.045= 4.18 (use only significant digits)
4.18 x 3.14= 13.13
13.13 x 3.78= 49.63
displacement is 49.63 cu. in. per cylinder
multiply by # of cylinders, and you get about 397 cu. in.
I'm sure I became more concerned about this than anyone else, but maybe this will help.
Nate
1964 F-100 Custom Cab 292 V-8 3 spd
1964 F-100 292 V-8 3 spd
1990 F-150 5.8L
Anyway, I found the specs and did the math. According to what I found, a 390 had a bore of 4.05 in and a 3.78 stroke. With it bored .040 over, you would increase displacement to 397 cubic inches.
Just wanted to clear it up, and apologize for the confusuion. Geometry was too long ago!
So, for one last time (to get it right)- figure displacement by squaring the radius of the bore, multiply that by pi (3.14), and then multiply the product by the stroke.
4.05 .040= 4.09
divide by 2 (to get radius)= 2.045
2.045 x 2.045= 4.18 (use only significant digits)
4.18 x 3.14= 13.13
13.13 x 3.78= 49.63
displacement is 49.63 cu. in. per cylinder
multiply by # of cylinders, and you get about 397 cu. in.
I'm sure I became more concerned about this than anyone else, but maybe this will help.
Nate
1964 F-100 Custom Cab 292 V-8 3 spd
1964 F-100 292 V-8 3 spd
1990 F-150 5.8L
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