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

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

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.

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

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.

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

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.

Re: SB/BB Cab Is there a difference?
 

and big blocks with an auto trans.

Re: SB/BB Cab Is there a difference?
 

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.

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

Re: SB/BB Cab Is there a difference?
 

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

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

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.

Re: SB/BB Cab Is there a difference?
 

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