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Old Apr 2, 2026 | 07:05 PM
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help on an engine swap

I have a 1976 F250 with a 390 that is whooped. i have a 460 out of a 1982 ford motorhome I'm planning on swapping into the truck. i have the mounts i got off of bronco grave yard and i have a bellhousing off a ford 400. my question is what flywheel and clutch should i use for this swap. I'm concerned about balancing and fitment or would it just be better to rebuild the engine? any help will be appreciated.
 

Last edited by Ryan Todd; Apr 2, 2026 at 07:36 PM.
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Old Apr 2, 2026 | 08:02 PM
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First things first, you'll be much farther ahead to find an actual 460 bellhousing off of an mid 80's pickup.

The reason I say that is because the USUAL way of going about using a 351M/400 bellhousing on a 429/460 is by using a 360/390 flywheel but that only applies to 1978 and earlier 460's due to the balance being moved to external in 1979. A 460 flywheel for a 1979 and later 460 will not fit in a 400 bellhousing (although I've seen some really redneck stuff using spacers between the block and bellhousing).
 
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Old Apr 2, 2026 | 09:25 PM
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L&L makes a flywheel and clutch kit for internal or external balance 460s. If you have the hatchet weight spacer on the crank snout then you have an external balance.
 
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Old Apr 2, 2026 | 10:30 PM
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I used the 351m/400 bell on my 86 460 in my highboy. I got a 12" diaphragm clutch and flywheel from rockauto for a 1986 460 with a 4 speed. I had to lightly grind the bolt bosses inside the bell but it was otherwise plug n play. All my clutch linkage lined up.
 

Last edited by nluttrell; Apr 2, 2026 at 10:31 PM.
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Old Apr 3, 2026 | 10:22 AM
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Rebuild the 390. you're gaining nothing the FE is a great engine and the expense of screwing up your highboy with a 460 will offset a lot of the rebuild cost. and maintain your resale value.
 
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Old Apr 3, 2026 | 10:56 AM
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Adding weight too .... plus all the bracket, exhaust, and other headaches. I'd rebuild the 390 .... and add stickers if it helps.
 

Last edited by tbear853; Apr 3, 2026 at 11:00 AM.
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Old Apr 3, 2026 | 01:28 PM
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Originally Posted by 440 sixpack
Rebuild the 390. you're gaining nothing the FE is a great engine and the expense of screwing up your highboy with a 460 will offset a lot of the rebuild cost. and maintain your resale value.
I'll add that you will gain absolutely nothing by going to a 200 horsepower malaise-era 460 out of a heavily emissions-ridden turd.
 

Last edited by cleatus12r; Apr 3, 2026 at 02:28 PM.
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Old Apr 3, 2026 | 04:03 PM
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does the 460 run good or does it need an OH too? You know its been worked hard its whole life.
You will need exhaust work to for the change over.
What's wrong with the 390? Is it stock?

I would take a 1968-71 460 over an FE every day of the week, especially if they were both OE stock.

Just a quick search a 460 only weighs 75 lbs more than a 460. That's only 9 gallons of gas.
 
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Old Apr 3, 2026 | 05:01 PM
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A factory 4V 390 will run circles around a typical factory low-pro 460. longevity wise both are great engines.
 
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Old Apr 3, 2026 | 05:28 PM
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Originally Posted by Rubiranch

I would take a 1968-71 460 over an FE every day of the week, especially if they were both OE stock.
.
I think most of us would. Starting in 1972 that all changed and EVERY engine became a worthless POS. When the only FE you could get after that was a low compression pickup 390 or a 360 (in the 4x4s), all bets are off. They ALL suck. In the case of the OP, he'd be time and money ahead (by a lot) to stick with the FE due to the complications and parts mix and match that has to occur to make the swap happen. 200 HP is 200 HP no matter the displacement.

 

Last edited by cleatus12r; Apr 3, 2026 at 05:31 PM.
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Old Apr 3, 2026 | 08:17 PM
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Originally Posted by 440 sixpack
A factory 4V 390 will run circles around a typical factory low-pro 460. longevity wise both are great engines.
You will get no argument from me over that from me.
I always felt the 400 in my '79 was just a big air pump that consumed a lot of gas and produced very little heat..
 
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Old Apr 3, 2026 | 08:28 PM
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Originally Posted by Rubiranch
You will get no argument from me over that from me.
I always felt the 400 in my '79 was just a big air pump that consumed a lot of gas and produced very little heat..
Much like a Harley Davidson. The perfect creation if the goal is turning fuel into noise without the bothersome side effect of power.
 
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Old Apr 3, 2026 | 08:57 PM
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It all starts with the compression, without that nothing matters. but if you just want an engine that puts out decent power and lives a long life the 390 is as good as any carbureted engine Ford ever made. nothing wrong with the 360 either it's just gutless.

there would be no upside to the 460 for that purpose, but there would be a lot of downside with the conversion.
 
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Old Apr 3, 2026 | 10:42 PM
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And Fords thrive on compression.
 
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Old Apr 4, 2026 | 05:51 AM
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Think of it as a "starter saver" feature.
 
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