SB BB differences in firewalls - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Dieselwrencher** · 07-30-2008, 07:21 PM

A while back I put a BBC in my 70 K20. I had to move the engine forward an inch or so because the 4wd's engine's sat so far back. During this project a friend of mine told me that the 2wd big block trucks have a different firewall. Is this true? I looked at my longhorn truck that had a 402 in it and it looks the same as this rusted out sbc cab I have. Has any one else heard this before? Thanks Ryan.

Jcentsr6 · 07-30-2008, 07:32 PM

I think I read something about 4X4 bigblock being diff somehow. (not the body...but the fitment)

**Dieselwrencher** · 07-30-2008, 07:35 PM

I know they never made a K20 with a big block from the factory, well I am pretty sure. But I am unsure of the firewall between the SBC trucks and the BBC trucks.

sameyrasmea72 · 07-30-2008, 07:47 PM

No differences in the firewall itself!!

JimKshortstep4x4 · 07-30-2008, 07:49 PM

Big blocks were not installed in 67-72 4x4 trucks. The fire walls are the same for the SBC and BBC 2 wd trucks except for the lower part on the right hand side. There is a heat shield fastened to the lower right hand side at the exhaust manifold location.

Jim

**Dieselwrencher** · 07-30-2008, 08:05 PM

Thanks Jim. I don't want to be misleading telling people that there is a BB cab. LOL

Jcentsr6 · 07-30-2008, 08:16 PM

Quote:

Originally Posted by Dieselwrencher

Thanks Jim. I don't want to be misleading telling people that there is a BB cab. LOL

Where can I get a Big Block cab at? I will pay big $$ for one! LOL

**Dieselwrencher** · 07-30-2008, 08:23 PM

Quote:

Originally Posted by Jcentsr6

Where can I get a Big Block cab at? I will pay big $$ for one! LOL

I will sell you one, or two. How many do you want? LOL

07-30-2008, 07:21 PM	#1
Dieselwrencher 6>8 Plugless........ Join Date: Sep 2007 Location: Prairie City, Ia Posts: 17,139	SB BB differences in firewalls A while back I put a BBC in my 70 K20. I had to move the engine forward an inch or so because the 4wd's engine's sat so far back. During this project a friend of mine told me that the 2wd big block trucks have a different firewall. Is this true? I looked at my longhorn truck that had a 402 in it and it looks the same as this rusted out sbc cab I have. Has any one else heard this before? Thanks Ryan.

07-30-2008, 07:32 PM	#2
Jcentsr6 Junior Member Join Date: Jul 2007 Location: Odenton, Md Posts: 552	Re: SB BB differences in firewalls I think I read something about 4X4 bigblock being diff somehow. (not the body...but the fitment) __________________ going to sell this one...looking for a SWB project next.

07-30-2008, 07:35 PM	#3
Dieselwrencher 6>8 Plugless........ Join Date: Sep 2007 Location: Prairie City, Ia Posts: 17,139	Re: SB BB differences in firewalls I know they never made a K20 with a big block from the factory, well I am pretty sure. But I am unsure of the firewall between the SBC trucks and the BBC trucks.

07-30-2008, 07:47 PM	#4
sameyrasmea72 Senior Member Join Date: Aug 2003 Location: Lubbock, Texas Posts: 2,443	Re: SB BB differences in firewalls No differences in the firewall itself!! __________________ 72 Cheyenne Super 80 Silverado Blazer 2wd

07-30-2008, 07:49 PM	#5
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: SB BB differences in firewalls Big blocks were not installed in 67-72 4x4 trucks. The fire walls are the same for the SBC and BBC 2 wd trucks except for the lower part on the right hand side. There is a heat shield fastened to the lower right hand side at the exhaust manifold location. 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

07-30-2008, 08:05 PM	#6
Dieselwrencher 6>8 Plugless........ Join Date: Sep 2007 Location: Prairie City, Ia Posts: 17,139	Re: SB BB differences in firewalls Thanks Jim. I don't want to be misleading telling people that there is a BB cab. LOL



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