putting a th 400 in my truck - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BowTieMan · 12-02-2005, 12:06 AM

I have a 70 2wd with a 350 and a th 350. What will I have to do to put a the 400 in? Something with the kickdown or something. And is it longer then the th 350?

jhow66 · 12-02-2005, 12:24 AM

400 longer --mount differant place (just slide crossmember back)--shorten driveshaft and change front yolk to a 400

BowTieMan · 12-02-2005, 12:32 AM

I just looked and I have the 9 in tail housing and a normal slip yoke design. Do you think I could run a one peice driveshaft with this trans in my long bed. I wont go past 61" for a drive shaft.

Longhorn Man · 12-02-2005, 01:07 AM

Do you have a LWB or a SWB?

409biscayne · 12-02-2005, 01:13 AM

Quote:

Originally Posted by BowTieMan

I have a 70 2wd with a 350 and a th 350. What will I have to do to put a the 400 in? Something with the kickdown or something. And is it longer then the th 350?

Any particular reason for going to the 400 ? I read somewhere they take something like 30 hp just to turn them , i'd trade a 72 t350 for a 400 ( who wouldn't) ha ha . Just my $.02

HeavyD · 12-02-2005, 03:00 AM

IIRC the Th400 kickdown is electric and for 67-70 the switch is located near the carb while on 71 up it is under the gas pedal.

gator2511 · 12-02-2005, 02:20 PM

Quote:

Originally Posted by BowTieMan

I just looked and I have the 9 in tail housing and a normal slip yoke design. Do you think I could run a one peice driveshaft with this trans in my long bed. I wont go past 61" for a drive shaft.

If you have a 9" tailshaft, the th400 with a 4" tailshaft will actually be 2 5/16" shorter than your present th350. I put a th400 in my K10 for pulling power and just to make the drive train stronger.

BowTieMan · 12-02-2005, 05:55 PM

I plan to make some power so I am going with the th400. I know 350's can take it but hey I allready have the 400.

Its a long bed, with the 9 in tail shaft. About how long would that driveshaft be?

gator2511 · 12-02-2005, 07:41 PM

Measure the driveshaft you have now, add 2 5/16" and thats how long it will be. You will have to measure yoke to yoke. Measure from the rear of your tranny yoke to the yoke on the rear end.

12-02-2005, 12:06 AM	#1
BowTieMan Registered User Join Date: Dec 2003 Location: Glendale Arizona Posts: 747	putting a th 400 in my truck I have a 70 2wd with a 350 and a th 350. What will I have to do to put a the 400 in? Something with the kickdown or something. And is it longer then the th 350? __________________ "A true hotrodder wouldn't be content untill he had created a car so violent, so hairy, so totally sick that the very act of dropping the hammer would result in instant death. Anything less results in the need to go faster." - Tony DeFeo

12-02-2005, 12:24 AM	#2
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: putting a th 400 in my truck 400 longer --mount differant place (just slide crossmember back)--shorten driveshaft and change front yolk to a 400 __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

12-02-2005, 12:32 AM	#3
BowTieMan Registered User Join Date: Dec 2003 Location: Glendale Arizona Posts: 747	Re: putting a th 400 in my truck I just looked and I have the 9 in tail housing and a normal slip yoke design. Do you think I could run a one peice driveshaft with this trans in my long bed. I wont go past 61" for a drive shaft. __________________ "A true hotrodder wouldn't be content untill he had created a car so violent, so hairy, so totally sick that the very act of dropping the hammer would result in instant death. Anything less results in the need to go faster." - Tony DeFeo

12-02-2005, 01:07 AM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: putting a th 400 in my truck Do you have a LWB or a SWB?

12-02-2005, 03:00 AM	#6
HeavyD Senior Member Join Date: Sep 2004 Location: Wakaw, Sask, Canada Posts: 3,180	Re: putting a th 400 in my truck IIRC the Th400 kickdown is electric and for 67-70 the switch is located near the carb while on 71 up it is under the gas pedal. __________________ "You can take the man out of PA, but you can't take PA out of the man"

12-02-2005, 05:55 PM	#8
BowTieMan Registered User Join Date: Dec 2003 Location: Glendale Arizona Posts: 747	Re: putting a th 400 in my truck I plan to make some power so I am going with the th400. I know 350's can take it but hey I allready have the 400. Its a long bed, with the 9 in tail shaft. About how long would that driveshaft be? __________________ "A true hotrodder wouldn't be content untill he had created a car so violent, so hairy, so totally sick that the very act of dropping the hammer would result in instant death. Anything less results in the need to go faster." - Tony DeFeo

12-02-2005, 07:41 PM	#9
gator2511 Registered User Join Date: Mar 2005 Location: tampa florida Posts: 776	Re: putting a th 400 in my truck Measure the driveshaft you have now, add 2 5/16" and thats how long it will be. You will have to measure yoke to yoke. Measure from the rear of your tranny yoke to the yoke on the rear end.



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