Th400 behind 250 l6 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

lswonmatt · 08-22-2017, 06:45 AM

Just got a th400 to go behind my 250 to replace my factory 3 speed wondeing if I needed to fabricate in a high hump since my truck is a low hump or Will the th400 go in fine without any clearance issues with the low hump?

**PGSigns** · 08-22-2017, 06:57 AM

If you can find a turbo 350 has a little lower first gear and a lot less rotating mass inside that takes power to turn. You may find it will work better with the 6. I also uses the same size out put yoke and u joint size. The 400 should just fit and may take a little work on the flange where the hump is welded in. You will need to remove the cross member that the bell housing is bolted to and install a rear trans mount.
Jimmy
Jimmy

**Captainfab** · 08-22-2017, 10:51 PM

I agree

Sell that TH400 and get yourself a TH350. If the TV cable wouldn't be such a difficult thing to do on the I6 I would suggest that trans.

Quote:

Originally Posted by PGSigns

If you can find a turbo 350 has a little lower first gear and a lot less rotating mass inside that takes power to turn. You may find it will work better with the 6. I also uses the same size out put yoke and u joint size. The 400 should just fit and may take a little work on the flange where the hump is welded in. You will need to remove the cross member that the bell housing is bolted to and install a rear trans mount.
Jimmy
Jimmy

**truckster** · 08-22-2017, 11:46 PM

Your 250 is going to work really hard to turn that 400. I agree with the others - if you want an auto, the 350 is a much better choice.

B. W. · 08-23-2017, 10:19 AM

I ran a TH400 behind a 250 then changed to a 292. It was a in a mud buggy, drove it every where, ran great. Ran mug bogs with it, never placed lower than 3rd (sometimes there were only three in my class!)

08-22-2017, 06:45 AM	#1
lswonmatt Registered User Join Date: May 2017 Location: Morgantown Kentucky Posts: 24	Th400 behind 250 l6 Just got a th400 to go behind my 250 to replace my factory 3 speed wondeing if I needed to fabricate in a high hump since my truck is a low hump or Will the th400 go in fine without any clearance issues with the low hump?

08-22-2017, 06:57 AM	#2
PGSigns Senior Member Join Date: Jan 2011 Location: Hayes Va Posts: 4,569	Re: Th400 behind 250 l6 If you can find a turbo 350 has a little lower first gear and a lot less rotating mass inside that takes power to turn. You may find it will work better with the 6. I also uses the same size out put yoke and u joint size. The 400 should just fit and may take a little work on the flange where the hump is welded in. You will need to remove the cross member that the bell housing is bolted to and install a rear trans mount. Jimmy Jimmy __________________ 60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic

08-22-2017, 11:46 PM	#4
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,806	Re: Th400 behind 250 l6 Your 250 is going to work really hard to turn that 400. I agree with the others - if you want an auto, the 350 is a much better choice. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

08-23-2017, 10:19 AM	#5
B. W. Registered User Join Date: Nov 2014 Location: Bigfork, Montana Posts: 1,137	Re: Th400 behind 250 l6 I ran a TH400 behind a 250 then changed to a 292. It was a in a mud buggy, drove it every where, ran great. Ran mug bogs with it, never placed lower than 3rd (sometimes there were only three in my class!)



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