390 or 400?

hollonator · 09-15-2009, 03:19 PM

lookin for some opinions here, i have a 32 ft. stock trailer that i pull with my dad's '78 f-250. he's thinkin about givin me the truck and it has a 390 in it, but i got a 400 sittin behind the shop that just needs some tlc...which would ya'll suggest?

BernieB · 09-15-2009, 04:56 PM

What kind of shape is the 390 in?

hollonator · 09-16-2009, 01:23 AM

it runs strong, sputters a bit til it warms up, dad believes it has about 120,000 miles on a rebuild

hotrodpc · 09-16-2009, 01:45 AM

390 is a good engine. I would run what it brung and keep it. Really, you are not going to see much improvement out of 10 cu in. I do beleive the 390 is also more common and easier to get parts for. I'd be lying if I said I knew exactly whats best, cuz I not all up to date on Fords, even those are older motors.

BernieB · 09-16-2009, 02:47 AM

With that many miles on it, and it having been rebuilt once before, I'm not so sure. Was it bored over during the rebuild? If so, how much?

What I'm thinking is that you might want to pull the 390 and rebuild it again, then put it back in. If the 400 is in decent shape, and you need the truck running, you might be able to drop it in while you rebuild the 390.

Six of one, half dozen of the other...

Oh, and a side note... You asked me earlier what sort of projects I was working on and I told you "nothing much". I think you jinxed me! Went to get the cat out of the garage earlier, so I could lock up and go to bed, when I realized the piece of rug inside the door to the laundry area was soaked. Ruptured water heater. And, according to the paperwork I have on it, the 15 year warranty on it expired about a week ago. (How DO they time those things so well?)

So, here it is at almost 5 AM and I'm waiting for Lowes to open so I can buy a water heater.

crabtruck · 09-16-2009, 03:32 AM

Next time Bernie disconnect that little wire
to the antenna before you install.
Where do you think they tested Onstar ?

hollonator · 09-16-2009, 03:36 AM

thats pretty tough luck there, didnt mean to jinx ya buddy

hollonator · 09-16-2009, 03:37 AM

hey guys i got a thread going in the "other turcks" forum as well labeled "desperately searching", take a look at that if you will its about an international cab.

crabtruck · 09-16-2009, 03:43 AM

Saw that, I'll keep eyes open, but it has been forever since I saw one.

Towtruck · 09-16-2009, 06:03 AM

The 390 and the 400 will have different transmission bellhousings unless you have a tranny for the 400 i would pull the 390 and rebuild it also. The 400 is built using a 351 clevland block. 351C, 351M (modified), and the 400 all use the same block with different cranks bores and strokes.

09-15-2009, 03:19 PM	#1
hollonator Full Member Join Date: Aug 2009 Location: virginia Posts: 102	390 or 400? lookin for some opinions here, i have a 32 ft. stock trailer that i pull with my dad's '78 f-250. he's thinkin about givin me the truck and it has a 390 in it, but i got a 400 sittin behind the shop that just needs some tlc...which would ya'll suggest?

09-15-2009, 04:56 PM	#2
BernieB Senior Member Join Date: Jul 2009 Location: Fredericksburg, VA Posts: 1,906	What kind of shape is the 390 in? __________________ If the guys who design 'em had to take one home, use it every day for 2 years, and do all the maint and repairs themselves, cars would have a button on the dash to change the oil, filters & plugs.

09-16-2009, 01:45 AM	#4
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,149	390 is a good engine. I would run what it brung and keep it. Really, you are not going to see much improvement out of 10 cu in. I do beleive the 390 is also more common and easier to get parts for. I'd be lying if I said I knew exactly whats best, cuz I not all up to date on Fords, even those are older motors. __________________ *Winners NEVER Quit , Quitters NEVER Win !!!*

09-16-2009, 02:47 AM	#5
BernieB Senior Member Join Date: Jul 2009 Location: Fredericksburg, VA Posts: 1,906	With that many miles on it, and it having been rebuilt once before, I'm not so sure. Was it bored over during the rebuild? If so, how much? What I'm thinking is that you might want to pull the 390 and rebuild it again, then put it back in. If the 400 is in decent shape, and you need the truck running, you might be able to drop it in while you rebuild the 390. Six of one, half dozen of the other... Oh, and a side note... You asked me earlier what sort of projects I was working on and I told you "nothing much". I think you jinxed me! Went to get the cat out of the garage earlier, so I could lock up and go to bed, when I realized the piece of rug inside the door to the laundry area was soaked. Ruptured water heater. And, according to the paperwork I have on it, the 15 year warranty on it expired about a week ago. (How DO they time those things so well?) So, here it is at almost 5 AM and I'm waiting for Lowes to open so I can buy a water heater. __________________ If the guys who design 'em had to take one home, use it every day for 2 years, and do all the maint and repairs themselves, cars would have a button on the dash to change the oil, filters & plugs.

09-16-2009, 06:03 AM	#10
Towtruck Senior Member Join Date: Aug 2009 Location: Ft.liqourdale, FL. Posts: 95	The 390 and the 400 will have different transmission bellhousings unless you have a tranny for the 400 i would pull the 390 and rebuild it also. The 400 is built using a 351 clevland block. 351C, 351M (modified), and the 400 all use the same block with different cranks bores and strokes. __________________ ASHES TO ASHES, DUST TO DUST, IF IT WEREN'T FOR CHEVY'S MY TOOLS WOULD RUST

09-16-2009, 01:23 AM	#3
hollonator Full Member Join Date: Aug 2009 Location: virginia Posts: 102	it runs strong, sputters a bit til it warms up, dad believes it has about 120,000 miles on a rebuild

09-16-2009, 03:32 AM	#6
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,366	Next time Bernie disconnect that little wire to the antenna before you install. Where do you think they tested Onstar ?

09-16-2009, 03:36 AM	#7
hollonator Full Member Join Date: Aug 2009 Location: virginia Posts: 102	thats pretty tough luck there, didnt mean to jinx ya buddy

09-16-2009, 03:37 AM	#8
hollonator Full Member Join Date: Aug 2009 Location: virginia Posts: 102	hey guys i got a thread going in the "other turcks" forum as well labeled "desperately searching", take a look at that if you will its about an international cab.

09-16-2009, 03:43 AM	#9
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,366	Saw that, I'll keep eyes open, but it has been forever since I saw one.

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