Big Block in a 4X4? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TLoz · 08-07-2009, 11:15 AM

Does anyone know why GM didn't offer a Big Block in a 4X4?

Keith Seymore · 08-07-2009, 11:30 AM

Probably because of torque multiplication; the driveline could handle the high range but in the low range 4wd setting you've doubled the torque to the axles. Usually the weak link is the front differential, but there could be concerns with front half shaft strength as well.

GM was/is very conservative when it comes to warranty items like this (areas where you or I as "hot rodders" might be a little more daring).

MHO -

K

TLoz · 08-07-2009, 11:35 AM

Keith,
Excellent info. Many thanks.

Keith Seymore · 08-07-2009, 11:46 AM

You are welcome.

One additional thought: today's computer controls give us another way to control the torque and allow the installation of bigger/more powerful engines. In an H2, for example, the 6.0L or 6.2L is putting out something like 390 HP (net)* which is more than enough to tear up a driveline. But - you can use the software to "torque manage", backing throttle out under certain conditions (like 4L or 4L Lock).

Naturally, back then we didn't have that level of control.

K

* the same engine in an Escalade is rated 403 HP.

Dooley · 08-07-2009, 11:22 PM

Quote:

Originally Posted by TLoz

Does anyone know why GM didn't offer a Big Block in a 4X4?

They started offering the 454 in the K30 series in 1982. My current V30 has a factory 454.

Keith Seymore · 08-08-2009, 09:37 AM

Quote:

Originally Posted by Dooley

They started offering the 454 in the K30 series in 1982. My current V30 has a factory 454.

After I wrote that wonderful dissertation?!....

Sounds right. IIRC, the 454 was available in pickups and a 2wd Suburban but not a 4wd Suburban.

K

ghettoluxury · 08-08-2009, 10:52 AM

And factory 454 trucks came with a Dana 60 instead of the Dana 44

TLoz · 08-08-2009, 10:43 PM

I'm pulling my 454 out of my 2wd burb and installing it in my 4wd burb. I've already used a bare block to relocate the crossmember and verified the motor mount location. I'll just take it easy when I'm in low. Doubt if I use it very often anyway.

willett · 08-09-2009, 09:30 PM

my '78 camper special 4x4 has a big block. i always assumed that it was stock.

there is a 14 bolt full floater in the rear, and a 44 ( i think) in the front with a turbo 400 mated to a 203.

perhaps its not stock?

1985-GMC · 08-09-2009, 11:54 PM

My 1983 chevy 4x4 1 Ton dually camper special has a 454, Dana 60, had the narrow 14 bolt but now has the Dana 70. It was a fire truck it's whole life.

Dooley · 08-10-2009, 08:00 PM

Quote:

Originally Posted by willett

my '78 camper special 4x4 has a big block. i always assumed that it was stock.

there is a 14 bolt full floater in the rear, and a 44 ( i think) in the front with a turbo 400 mated to a 203.

perhaps its not stock?

Your 1978 4x4 Camper Special did not come equipped with a big block from factory. The 400 small block was the largest engine available in the 4x4 series light trucks in 1978.

08-07-2009, 11:15 AM	#1
TLoz Registered User Join Date: Dec 2003 Location: Indy Posts: 326	Big Block in a 4X4? Does anyone know why GM didn't offer a Big Block in a 4X4?

08-07-2009, 11:30 AM	#2
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,226	Re: Big Block in a 4X4? Probably because of torque multiplication; the driveline could handle the high range but in the low range 4wd setting you've doubled the torque to the axles. Usually the weak link is the front differential, but there could be concerns with front half shaft strength as well. GM was/is very conservative when it comes to warranty items like this (areas where you or I as "hot rodders" might be a little more daring). MHO - K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ Last edited by Keith Seymore; 08-07-2009 at 11:42 AM.

08-07-2009, 11:35 AM	#3
TLoz Registered User Join Date: Dec 2003 Location: Indy Posts: 326	Re: Big Block in a 4X4? Keith, Excellent info. Many thanks.

08-07-2009, 11:46 AM	#4
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,226	Re: Big Block in a 4X4? You are welcome. One additional thought: today's computer controls give us another way to control the torque and allow the installation of bigger/more powerful engines. In an H2, for example, the 6.0L or 6.2L is putting out something like 390 HP (net)* which is more than enough to tear up a driveline. But - you can use the software to "torque manage", backing throttle out under certain conditions (like 4L or 4L Lock). Naturally, back then we didn't have that level of control. K * the same engine in an Escalade is rated 403 HP. __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ Last edited by Keith Seymore; 08-07-2009 at 11:47 AM.

08-08-2009, 10:52 AM	#7
ghettoluxury Registered User Join Date: Apr 2009 Location: Waynesfield Ohio Posts: 1,991	Re: Big Block in a 4X4? And factory 454 trucks came with a Dana 60 instead of the Dana 44 __________________ 1949 Five Window, 1973 Step Side, 2000 Z71

08-08-2009, 10:43 PM	#8
TLoz Registered User Join Date: Dec 2003 Location: Indy Posts: 326	Re: Big Block in a 4X4? I'm pulling my 454 out of my 2wd burb and installing it in my 4wd burb. I've already used a bare block to relocate the crossmember and verified the motor mount location. I'll just take it easy when I'm in low. Doubt if I use it very often anyway.

08-09-2009, 09:30 PM	#9
willett Another Day, Another Dollar Join Date: Nov 2008 Location: North Vancouver, BC Posts: 1,316	Re: Big Block in a 4X4? my '78 camper special 4x4 has a big block. i always assumed that it was stock. there is a 14 bolt full floater in the rear, and a 44 ( i think) in the front with a turbo 400 mated to a 203. perhaps its not stock? __________________ -78 K20 Cheyenne 454 long box, 4" lift, 35" MT's, '84 cab, '80 box "its hip to be square"

08-09-2009, 11:54 PM	#10
1985-GMC Chevy Enthusiast Join Date: Jul 2009 Location: Canyon Lake Texas Posts: 2,024	Re: Big Block in a 4X4? My 1983 chevy 4x4 1 Ton dually camper special has a 454, Dana 60, had the narrow 14 bolt but now has the Dana 70. It was a fire truck it's whole life.



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