Th400 and hi-hump question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BCOWANWHEELS · 01-13-2012, 09:35 PM

If I change over from a th350 (low hump) to a th400 in my 1970 lwb do I have to install the high hump in the floor ? i sure would hate to cut my floor board. thanks for the help
bob

crazy longhorn · 01-13-2012, 09:45 PM

Small block....NO! my 69 came from the factory with a low hump (350/400 turbo). The BB trucks are a different story tho.... crazyL

BCOWANWHEELS · 01-13-2012, 09:47 PM

so with my 350 sbc a th400 wont fit without installing a hi-hump right ?

**FirstOwner69** · 01-13-2012, 10:11 PM

No problem putting a TH400/350 V8 combo in a truck with a small hump. My 69 came that way as Crazy Longhorn said his did.

BCOWANWHEELS · 01-13-2012, 10:13 PM

thanks fellas I sure didnt want to cut my truck floorboard out.
bob

Beat68CST · 01-13-2012, 11:45 PM

You can fit a BBC and a 400 on a low hump.

You can fit a Cummins and a 47RH under a low hump too (;

BCOWANWHEELS · 01-14-2012, 01:15 AM

i also have a cummins 4bt with a A518 I was thinking about for a future truck.

Beat68CST · 01-14-2012, 01:39 AM

You have to cut the main crossmember and flatten it out to about only 2 1/2 inches tall so you can get the motor to sit flat

BCOWANWHEELS · 01-14-2012, 01:45 AM

Beat68cst,
you dont have to do this with sbc and th400 swap do you ?

Beat68CST · 01-14-2012, 02:01 AM

Nooo, SBC and T400 fit perfect. Everything will clear nicely.

You can shoe horn a BBC and T400 under a low hump too.

**DaHos** · 01-14-2012, 11:09 AM

Quote:

Originally Posted by Beat68CST

You have to cut the main crossmember and flatten it out to about only 2 1/2 inches tall so you can get the motor to sit flat

Anyone have clearance photos of the BB and th400 with low hump? Only issue I can see is the longer tail shaft.

BCOWANWHEELS · 01-14-2012, 08:05 PM

Theres plenty of room for the longer tailshaft in fact you could run the longest tail shaft trans and possiblt run a 1 piece drive shaft. I have a gear vendors o.d. Going behind my th400 in my 1970 truck and a 1 piece shaft with 1350 joints is the route i,am going.

01-13-2012, 09:35 PM	#1
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Th400 and hi-hump question If I change over from a th350 (low hump) to a th400 in my 1970 lwb do I have to install the high hump in the floor ? i sure would hate to cut my floor board. thanks for the help bob __________________ I BELIEVE IN JOHN 3:16

01-13-2012, 09:45 PM	#2
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Re: Th400 and hi-hump question Small block....NO! my 69 came from the factory with a low hump (350/400 turbo). The BB trucks are a different story tho.... crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

01-13-2012, 09:47 PM	#3
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: Th400 and hi-hump question so with my 350 sbc a th400 wont fit without installing a hi-hump right ? __________________ I BELIEVE IN JOHN 3:16

01-13-2012, 10:11 PM	#4
FirstOwner69 Registered User Join Date: May 2010 Location: Wisconsin & Arizona Posts: 4,854	Re: Th400 and hi-hump question No problem putting a TH400/350 V8 combo in a truck with a small hump. My 69 came that way as Crazy Longhorn said his did.

01-13-2012, 10:13 PM	#5
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: Th400 and hi-hump question thanks fellas I sure didnt want to cut my truck floorboard out. bob __________________ I BELIEVE IN JOHN 3:16

01-13-2012, 11:45 PM	#6
Beat68CST Registered User Join Date: Oct 2010 Location: Buckeye Arizona Posts: 470	Re: Th400 and hi-hump question You can fit a BBC and a 400 on a low hump. You can fit a Cummins and a 47RH under a low hump too (;

01-14-2012, 01:15 AM	#7
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: Th400 and hi-hump question i also have a cummins 4bt with a A518 I was thinking about for a future truck. __________________ I BELIEVE IN JOHN 3:16

01-14-2012, 01:39 AM	#8
Beat68CST Registered User Join Date: Oct 2010 Location: Buckeye Arizona Posts: 470	Re: Th400 and hi-hump question You have to cut the main crossmember and flatten it out to about only 2 1/2 inches tall so you can get the motor to sit flat

01-14-2012, 01:45 AM	#9
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: Th400 and hi-hump question Beat68cst, you dont have to do this with sbc and th400 swap do you ? __________________ I BELIEVE IN JOHN 3:16

01-14-2012, 02:01 AM	#10
Beat68CST Registered User Join Date: Oct 2010 Location: Buckeye Arizona Posts: 470	Re: Th400 and hi-hump question Nooo, SBC and T400 fit perfect. Everything will clear nicely. You can shoe horn a BBC and T400 under a low hump too.

01-14-2012, 08:05 PM	#12
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: Th400 and hi-hump question Theres plenty of room for the longer tailshaft in fact you could run the longest tail shaft trans and possiblt run a 1 piece drive shaft. I have a gear vendors o.d. Going behind my th400 in my 1970 truck and a 1 piece shaft with 1350 joints is the route i,am going. __________________ I BELIEVE IN JOHN 3:16



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