SB/BB Cab Is there a difference? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BBC Motorhead · 12-06-2010, 10:10 PM

I am planning on putting a BB in a 71 shortbox that originally came with a SB. I am wondering what kind of problems I can expect in doing this. This truck is totally disassembled and want to mock the engine and tranny up before it goes to powdercoat. Can someone steer me in the right direction? Thanks

**71blksuper4x4** · 12-06-2010, 10:37 PM

Big Block trucks were large hump cabs as far as I know. Any that I have ever seen or had, have always been large humped. Longhornman (member) might know more than I on this. Other than that, there is no difference besides the bolt on heat shield for the firewall to help with the heat of the big block manifold. Trevor

**too much stuff** · 12-06-2010, 10:39 PM

Not all big block trucks had the high hump. It also depends on what trans is behind it. I had a stock 72 cheyenne big block with a 3 on the tree and a low hump.

**71blksuper4x4** · 12-06-2010, 10:48 PM

Thanks Eric, I was trying to remember from a talk about high humps awhile back. I think Longhornman said they made some without the high hump. All the ones I ever run across have had the th400. Trevor

Longhorn Man · 12-07-2010, 12:22 AM

the 3 speed big blocks were the only ones that were supposed to get the low himp, but that combo is far and few between.

GOPAPA · 12-07-2010, 01:05 AM

I see no problems with the cab ..but if you put a 4 core radiator in it you will want to move the bb motor back some maybe to the next hole so the clutch fan is not up against the radiator..and go with a short water pump..
You might want a heat shield that came on the bb cabs that bolts to the fire wall on the passenger side next to the exhaust manifold.
Also a heat shield for the starter if you use the big starter as again the exhaust manifold is bigger and hotter and close to the starter.
The 350th fits with out a hump and I believe the 400th will also ,

And I think the front coils are a heavier coil for the bb trucks compared to the sb..

just some stuff tha I have learned on here I felt like sharing just in case you didnt know ..gp Larry

Transformula · 12-07-2010, 01:19 AM

Huh Huh... you said hump! ... The high hump is usually for the floor shifted manuals, and 4 wheel drive models.

Longhorn Man · 12-07-2010, 10:08 AM

Quote:

Originally Posted by Transformula

Huh Huh... you said hump! ... The high hump is usually for the floor shifted manuals, and 4 wheel drive models.

and big blocks with an auto trans.

Shyguy · 12-07-2010, 11:15 AM

Quote:

Originally Posted by GOPAPA

I see no problems with the cab ..but if you put a 4 core radiator in it you will want to move the bb motor back some maybe to the next hole so the clutch fan is not up against the radiator..and go with a short water pump..
You might want a heat shield that came on the bb cabs that bolts to the fire wall on the passenger side next to the exhaust manifold.
Also a heat shield for the starter if you use the big starter as again the exhaust manifold is bigger and hotter and close to the starter.
The 350th fits with out a hump and I believe the 400th will also ,

And I think the front coils are a heavier coil for the bb trucks compared to the sb..

just some stuff tha I have learned on here I felt like sharing just in case you didnt know ..gp Larry

I think you are right about the front coils being heavier duty with the BBs. We put a 454 in my '71 and it lowered the frontend a couple of inches. It still rides and handles ok, but I might put a set of 3/4 ton springs in it I have.

JimKshortstep4x4 · 12-07-2010, 08:56 PM

My son's 69 GMC with the original 396 in it has a low hump. It was a 3 speed transmission. Big blocks with 3 speeds are pretty rare with what I have seen.

We did put a 402 along with a Th 400 in a 72 C-10 with a low hump. We did not have any issues.

Jim

GOPAPA · 12-07-2010, 10:42 PM

Quote:

Originally Posted by Shyguy

I think you are right about the front coils being heavier duty with the BBs. We put a 454 in my '71 and it lowered the frontend a couple of inches. It still rides and handles ok, but I might put a set of 3/4 ton springs in it I have.

I went to my notes and what the coils for a BB engine truck are ,,,is none other thant 3/4 ton stock coils.. Had to push my reset button to remember where I stored that info.. gp Larry

BBC Motorhead · 12-08-2010, 09:06 PM

Thanks a ton for all the info guys. My biggest worry was having the motor too close to the firewall. I plan on using a big radiator with electic fans. I want to use some custom motor mounts and I am wondering what holes to use on the frame. Thanks again

Longhorn Man · 12-09-2010, 12:19 AM

if you use custom motor mounts, then there is no way we can tell you what holes to use... it'll be custom.

GOPAPA · 12-09-2010, 12:40 AM

Quote:

Originally Posted by BBC Motorhead

Thanks a ton for all the info guys. My biggest worry was having the motor too close to the firewall. I plan on using a big radiator with electic fans. I want to use some custom motor mounts and I am wondering what holes to use on the frame. Thanks again

Curious,,why is it you are not using BB motor mounts .. I am pretty sure there are members here in the parts for sale forum that would have some to sell you ..

I have BB mounts and I backed the motor up some to stay away from the radiator and my Distributor is away from the firewall enough and not hard to get to.. just saying in case you didnt know ..Gp Larry

12-06-2010, 10:10 PM	#1
BBC Motorhead Registered User Join Date: Nov 2010 Location: Bismarck North Dakota Posts: 71	SB/BB Cab Is there a difference? I am planning on putting a BB in a 71 shortbox that originally came with a SB. I am wondering what kind of problems I can expect in doing this. This truck is totally disassembled and want to mock the engine and tranny up before it goes to powdercoat. Can someone steer me in the right direction? Thanks

12-06-2010, 10:37 PM	#2
71blksuper4x4 SWB 4x4 Collector Join Date: Jun 2001 Location: Osage City, KS Posts: 5,155	Re: SB/BB Cab Is there a difference? Big Block trucks were large hump cabs as far as I know. Any that I have ever seen or had, have always been large humped. Longhornman (member) might know more than I on this. Other than that, there is no difference besides the bolt on heat shield for the firewall to help with the heat of the big block manifold. Trevor __________________ TREVOR 1970 CST swb 4x4 (speedwarning,cruise,tilt,tach,8track, original red shoulder belts,tow hooks) 1972 Jimmy (soon to be Hickey cloned) 1971 Cheyenne Super 4x4 swb (tilt,tach,buckets, original blue shoulder belts,am/fm,cruise,tow hooks, dealer 8 track) 1972 Cheyenne Super K20 4x4 Custom Camper (tilt, tach, am/fm, tow hooks, bed toolbox, aux gas tank 1972 Cheyenne Super Crew Cab K30 4x4 Duramax, Allison, np205, buckets, tow hooks (CURRENT PROJECT) http://67-72chevytrucks.com/vboard/s...d.php?t=624819 1989 V3500 Crew Cab (454tbi, NV4500, np205) 1970 Chevelle SS (LS5 454,th400,8track,buckets,tach) :2004 Jeep Wrangler Rubicon (daily driver) WTB: 1968-70 Cruise Control Lever

12-06-2010, 10:39 PM	#3
too much stuff Roadtrip! Join Date: Feb 2003 Location: Grand Rapids MN Posts: 13,768	Re: SB/BB Cab Is there a difference? Not all big block trucks had the high hump. It also depends on what trans is behind it. I had a stock 72 cheyenne big block with a 3 on the tree and a low hump. __________________ 67 gmc custom lwb dakota truck. Sold...And bought back 69 swb 4x4 project (in progress) 70 c-10 lwb texas truck 70 4x4/BB/bkts/posi/tach(retired) 70 swb (wifes) 70 jimmy camper 71 K-5 factory 2wd 71 cheyenne 4x4/tach/posi/ plow rig 71 Cheyenne20 BB, buckets, tach, tilt, 4 speed 72 jimmy CST wyoming rig 72 jimmy Colorado rig 72 lifted texas 4x4 3/4 ton burb 65 fury conv. 383/auto 65 chrysler 300 "L" 413 auto

12-06-2010, 10:48 PM	#4
71blksuper4x4 SWB 4x4 Collector Join Date: Jun 2001 Location: Osage City, KS Posts: 5,155	Re: SB/BB Cab Is there a difference? Thanks Eric, I was trying to remember from a talk about high humps awhile back. I think Longhornman said they made some without the high hump. All the ones I ever run across have had the th400. Trevor __________________ TREVOR 1970 CST swb 4x4 (speedwarning,cruise,tilt,tach,8track, original red shoulder belts,tow hooks) 1972 Jimmy (soon to be Hickey cloned) 1971 Cheyenne Super 4x4 swb (tilt,tach,buckets, original blue shoulder belts,am/fm,cruise,tow hooks, dealer 8 track) 1972 Cheyenne Super K20 4x4 Custom Camper (tilt, tach, am/fm, tow hooks, bed toolbox, aux gas tank 1972 Cheyenne Super Crew Cab K30 4x4 Duramax, Allison, np205, buckets, tow hooks (CURRENT PROJECT) http://67-72chevytrucks.com/vboard/s...d.php?t=624819 1989 V3500 Crew Cab (454tbi, NV4500, np205) 1970 Chevelle SS (LS5 454,th400,8track,buckets,tach) :2004 Jeep Wrangler Rubicon (daily driver) WTB: 1968-70 Cruise Control Lever

12-07-2010, 12:22 AM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: SB/BB Cab Is there a difference? the 3 speed big blocks were the only ones that were supposed to get the low himp, but that combo is far and few between.

12-07-2010, 01:05 AM	#6
GOPAPA Senior Member Join Date: Oct 2007 Location: Nampa Idaho Posts: 7,551	Re: SB/BB Cab Is there a difference? I see no problems with the cab ..but if you put a 4 core radiator in it you will want to move the bb motor back some maybe to the next hole so the clutch fan is not up against the radiator..and go with a short water pump.. You might want a heat shield that came on the bb cabs that bolts to the fire wall on the passenger side next to the exhaust manifold. Also a heat shield for the starter if you use the big starter as again the exhaust manifold is bigger and hotter and close to the starter. The 350th fits with out a hump and I believe the 400th will also , And I think the front coils are a heavier coil for the bb trucks compared to the sb.. just some stuff tha I have learned on here I felt like sharing just in case you didnt know ..gp Larry

12-07-2010, 01:19 AM	#7
Transformula Registered User Join Date: Nov 2010 Location: Las Vegas, Nevada Posts: 160	Re: SB/BB Cab Is there a difference? Huh Huh... you said hump! ... The high hump is usually for the floor shifted manuals, and 4 wheel drive models.

12-07-2010, 08:56 PM	#10
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: SB/BB Cab Is there a difference? My son's 69 GMC with the original 396 in it has a low hump. It was a 3 speed transmission. Big blocks with 3 speeds are pretty rare with what I have seen. We did put a 402 along with a Th 400 in a 72 C-10 with a low hump. We did not have any issues. 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

12-08-2010, 09:06 PM	#12
BBC Motorhead Registered User Join Date: Nov 2010 Location: Bismarck North Dakota Posts: 71	Re: SB/BB Cab Is there a difference? Thanks a ton for all the info guys. My biggest worry was having the motor too close to the firewall. I plan on using a big radiator with electic fans. I want to use some custom motor mounts and I am wondering what holes to use on the frame. Thanks again

12-09-2010, 12:19 AM	#13
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: SB/BB Cab Is there a difference? if you use custom motor mounts, then there is no way we can tell you what holes to use... it'll be custom.



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