F150 4x4 1978 model
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F150 4x4 1978 model
My son and I just bought this truck to restore. It actually runs pretty good. It has a 351m/400 engine. How can I determine the actual cubic inches and horespower rating of this engine; is it 351 or 400? Is there a place I can research by the serial number?
We are new to this site so your understanding will be appreciated. Also, the individual that owned this truck put different gearing in the rear differential than the front end. Is there a way to determine what they originally were so that I can just fix the rear?
We are new to this site so your understanding will be appreciated. Also, the individual that owned this truck put different gearing in the rear differential than the front end. Is there a way to determine what they originally were so that I can just fix the rear?
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Joined: May 2001
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F150 4x4 1978 model
[font size="1" color="#FF0000"]LAST EDITED ON 30-Jun-01 AT 02:07 AM (EST)[/font][p]Other than measuring the stroke, I can't help with the displacement. I have both and they look, sound, and run exactly the same.
The easiest way to determine the gearing is to remove the front diff. cover and count the ring/pinion teeth and divide ring by pinion. e.g. 35 ring gear teeth divided by 10 pinion teeth = 3.5 or 3.50 gears.
On edit: For the gear ratio, I'm assuming the tags are missing from the cover bolts.
BFM
The easiest way to determine the gearing is to remove the front diff. cover and count the ring/pinion teeth and divide ring by pinion. e.g. 35 ring gear teeth divided by 10 pinion teeth = 3.5 or 3.50 gears.
On edit: For the gear ratio, I'm assuming the tags are missing from the cover bolts.
BFM
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F150 4x4 1978 model
About the 351m/400 it should be labeld by on the in take manifold or by the serial numbers around the driver's side door. I personally would NOT us 4 wheel drive until till you get the same gear ratio because it could burn one set or the other because of the differnt speed. Again the gear ratio is labled on the inside door track of the driver's side. if you are wourndering how i know this its becuase i have a 77 4x4.
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F150 4x4 1978 model
The engine should have a white label on the valve cover on the drivers side. It will tell you displacement and engine family. Most of those "m" motors did not have a whole lot of power. As for the rears they should have the metalic tag on the cover bolts. it will state the ratio of the differental. A lot can happen in all those years so counting teeth is the only certain way to determine the ratio. Good luck on your truck.
