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Aug 11, 2023 | 04:51 PM

ynot321AB

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Am thinking of putting a 351 with manual tranny into my '50 F-1. I need to know what rear end it should have put in and how hard it is to change out the rear end.

Aug 11, 2023 | 05:28 PM

moejr

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From: Mendon, Massachusetts

A direct bolt in swap rear end use a 9" axle housing from 1957-1972 F100.

Aug 11, 2023 | 06:51 PM

ynot321AB

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So I gotta change the whole rear axle or just the inside of the rear end?

Aug 11, 2023 | 07:14 PM

FuzzFace2

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You did not say what rear ratio is in the axle now?
Also why do you think you need to change it?
Dave ----

Aug 11, 2023 | 07:17 PM

moejr

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You need to swap the whole rear end. You can upgrade engine & transmission and still keep the stock rear end if it's in good shape.

Aug 11, 2023 | 07:19 PM

ynot321AB

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I was told before that I could leave the same rear end in as it is the one that came with the '50 but was also told with the original the most speed I could expect to get would be around 50 MPH

Aug 11, 2023 | 07:32 PM

moejr

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With a stock 49 engine I would expect more than 50mph ..... HP & gear ratio will determine your speed not what type of rear end you have. Stock rear ends work fine with mild engine / trans upgrades and can handle up 300hp.....so they say.

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Aug 11, 2023 | 07:39 PM

ynot321AB

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Thanks for the information, I am trying to leave the pickup as original as possible. had a 239 in it but the block was cracked and haven't had any luck finding another

Aug 11, 2023 | 07:57 PM

#10

moejr

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Can you post some pics? Don't give up on stock flatty motors, lots of resources out there.

Aug 11, 2023 | 08:20 PM

#11

ynot321AB

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Do you know of anyone that has just a block for a 239? The old style with the distributor on the right front. I saved all of the pieces from the old engine and looking for a block

Aug 11, 2023 | 08:44 PM

#12

moejr

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From: Mendon, Massachusetts

I don't but Google it and you will find a ton of resources on the subject.

Aug 11, 2023 | 09:10 PM

#13

52 Merc

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A 351 or even a 302 would make a really nice driver out of your truck. The stock rear typically came with 3.91-4.11 gears and the rpm's tend to run high at highway speeds. The modern v8's would be much more comfortable with something closer to 3.25 and let you drive on the freeway more comfortably. The easiest and cheapest way to do that is with the F100 9" swap as mentioned. And yes, that does mean replacing the entire rear axle assembly. It's not as difficult as it sounds.