High Hump trans tunnel - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Richard Dobson · 09-10-2007, 07:50 AM

I am putting a 396 big block with a turbo 400 from a 3/4 ton into a 1/2 ton with a 6 cyl 3-speed.. The 3/4 ton has a high hump trans tunnel and the 1/2 ton don't. Will the big block combo go into the 1/2 ton without the high hump trans tunnel?

JimKshortstep4x4 · 09-10-2007, 09:43 AM

We put a 402 bbc and TH 400 in my son's 72 using all stock mounts and the clearances are good. (He has a 72 C-10 with a low hump in it.

Jim

**LockDoc** · 09-10-2007, 10:02 AM

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My white truck (67 c10) also has a big block/TH400 with a low hump floor. If you have any clearance problems I would check the condition of the rubber cab mounts. They may need to be replaced.

LockDoc

Richard Dobson · 09-10-2007, 12:19 PM

Can I ask what driveshaft length you guys used, my truck has a 1-piece drive shaft but it's a short bed. The engine donor truck is a long bed. Is there a stock drive shaft available for my truck? Thanks for the replies.

Frizzle Fry · 09-10-2007, 12:27 PM

x3 my factory 396/400 2wd 1/2ton burb has a low hump.

Richard Dobson · 09-10-2007, 12:37 PM

Another question? How much of a change will I see in the truck's stance changing from a 6 cyl 3-speed to the 396 w/turbo 400? I have a 2.5 front and 3.5 rear drop. The weight diff in the engines will make some change won't it? Sorry about so many questions. I guess I am getting too fired up.

**LockDoc** · 09-10-2007, 02:17 PM

Quote:

Originally Posted by Richard Dobson

Can I ask what driveshaft length you guys used, my truck has a 1-piece drive shaft but it's a short bed. The engine donor truck is a long bed. Is there a stock drive shaft available for my truck? Thanks for the replies.

I don't remember what mine measured. My truck is a short bed also.

The big block will settle the front down a little but not as much as you think it would.

lockDoc

Frizzle Fry · 09-11-2007, 02:34 PM

Quote:

Originally Posted by Richard Dobson

Another question? How much of a change will I see in the truck's stance changing from a 6 cyl 3-speed to the 396 w/turbo 400? I have a 2.5 front and 3.5 rear drop. The weight diff in the engines will make some change won't it? Sorry about so many questions. I guess I am getting too fired up.

There are different springs for big blocks. But... I drove the burb with SBC springs and a BBC/400 and it rode fine IMO. It will sit lower, but I couldn't say how much. I would guess about 1/2"

09-10-2007, 07:50 AM	#1
Richard Dobson Registered User Join Date: Apr 2003 Location: Easley, South Carolina Posts: 491	High Hump trans tunnel I am putting a 396 big block with a turbo 400 from a 3/4 ton into a 1/2 ton with a 6 cyl 3-speed.. The 3/4 ton has a high hump trans tunnel and the 1/2 ton don't. Will the big block combo go into the 1/2 ton without the high hump trans tunnel? __________________ Richard Dobson

09-10-2007, 09:43 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: High Hump trans tunnel We put a 402 bbc and TH 400 in my son's 72 using all stock mounts and the clearances are good. (He has a 72 C-10 with a low hump in it. Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

09-10-2007, 10:02 AM	#3
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,648	Re: High Hump trans tunnel - My white truck (67 c10) also has a big block/TH400 with a low hump floor. If you have any clearance problems I would check the condition of the rubber cab mounts. They may need to be replaced. LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - Last edited by LockDoc; 09-10-2007 at 10:03 AM.

09-10-2007, 12:19 PM	#4
Richard Dobson Registered User Join Date: Apr 2003 Location: Easley, South Carolina Posts: 491	Re: High Hump trans tunnel Can I ask what driveshaft length you guys used, my truck has a 1-piece drive shaft but it's a short bed. The engine donor truck is a long bed. Is there a stock drive shaft available for my truck? Thanks for the replies. __________________ Richard Dobson

09-10-2007, 12:27 PM	#5
Frizzle Fry Registered User Join Date: Aug 2005 Location: Hillsboro Oregon Posts: 6,449	Re: High Hump trans tunnel x3 my factory 396/400 2wd 1/2ton burb has a low hump.

09-10-2007, 12:37 PM	#6
Richard Dobson Registered User Join Date: Apr 2003 Location: Easley, South Carolina Posts: 491	Re: High Hump trans tunnel Another question? How much of a change will I see in the truck's stance changing from a 6 cyl 3-speed to the 396 w/turbo 400? I have a 2.5 front and 3.5 rear drop. The weight diff in the engines will make some change won't it? Sorry about so many questions. I guess I am getting too fired up. __________________ Richard Dobson



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