Engine Mount - BB to SB - The 1947 - Present Chevrolet & GMC Truck Message Board Network

PartyPooper · 02-12-2007, 12:33 AM

Hello All,

I'm working on my 1970 GMC 3/4 Ton and need to rebuild my engine (with limited funds of course). I've got a 402 and I'm thinking of selling it and replacing it with a 350. Can I switch the BB engine mount towers to the replacement tube style engine mount brackets and will the SB 350 be in the same position for tranny and drive shaft alignment (front to back)?

Thanks

RACINJASON22 · 02-12-2007, 01:00 AM

WOW I'm a small block guy through and through, but whats your reasoning on changeing to a SBC from a BBC interested in hearing your thoughts.

Longhorn Man · 02-12-2007, 01:08 AM

he's on limited funds.
he can sell the pullies and brackets ALONE.. and get a good used small block with that money... not a junk yard engine, a good engine.
BBC motors are way over rated, and people will pay dearly for the parts to make one fit.

PartyPooper · 02-12-2007, 02:56 AM

I'm changing for the exact reasons Longhorn described. The cost of rebuild kits, machine work, motor mounts, and such are item per item more expensive with the BB. I'm hoping with what I can sell from the BB setup I can get myself a good start into a nice 350.

I just want to make sure I'm not over simpifying the process.

FLEET72 · 02-12-2007, 04:24 AM

Quote:

Originally Posted by PartyPooper

Hello All,
I'm working on my 1970 GMC 3/4 Ton and need to rebuild my engine (with limited funds of course). I've got a 402 and I'm thinking of selling it and replacing it with a 350. Can I switch the BB engine mount towers to the replacement tube style engine mount brackets and will the SB 350 be in the same position for tranny and drive shaft alignment (front to back)? Thanks

It would seem to me that the frames are the same whether a BB or SB resides between the rails. My 72 came from the factory with a 402 / 4 speed and someone came along and swapped a 300hp Z28 motor / TH350 in it.

**kwmech** · 02-12-2007, 10:51 AM

Yo do not have to chnge anything as far as mounts go. Using the big block towers for your small block will keep the trans in the same place. If you do this, it will be easier to use a later model bracket setup and the long water pump with the big block shroud. You can even go to a cleaner sepentine setup if the budget allows

PartyPooper · 02-15-2007, 07:44 PM

As most newcomers do, first let me apologize for my ignorance...

Would this be the proper mount to use on the BB tower (it's from the Truckshop catalog in Orange CA)?

corn · 02-15-2007, 08:33 PM

I had a 350 in my big block truck for a while. Took the mounts off the 396 & bolted them on the 350. Dropped on the bb towers like it was made for it. I had no issues at all. Did have headers though so not sure on manifolds but I doubt they would be a problem either...

02-12-2007, 12:33 AM	#1
PartyPooper Registered User Join Date: Nov 2006 Location: Yorba Linda CA Posts: 22	Engine Mount - BB to SB Hello All, I'm working on my 1970 GMC 3/4 Ton and need to rebuild my engine (with limited funds of course). I've got a 402 and I'm thinking of selling it and replacing it with a 350. Can I switch the BB engine mount towers to the replacement tube style engine mount brackets and will the SB 350 be in the same position for tranny and drive shaft alignment (front to back)? Thanks

02-12-2007, 01:00 AM	#2
RACINJASON22 GEARHEAD Join Date: Jan 2007 Location: CENTRAL,PA Posts: 2,284	Re: Engine Mount - BB to SB WOW I'm a small block guy through and through, but whats your reasoning on changeing to a SBC from a BBC interested in hearing your thoughts. __________________ 72 SWB 2WD MY PROJECT 72 LWB 4X4 FUTURE PROJECT SUBSCRIBE HEREBOARD VENDORS HERE NORWOOD MEET SURVIVOR!

02-12-2007, 01:08 AM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Engine Mount - BB to SB he's on limited funds. he can sell the pullies and brackets ALONE.. and get a good used small block with that money... not a junk yard engine, a good engine. BBC motors are way over rated, and people will pay dearly for the parts to make one fit.

02-12-2007, 02:56 AM	#4
PartyPooper Registered User Join Date: Nov 2006 Location: Yorba Linda CA Posts: 22	Re: Engine Mount - BB to SB I'm changing for the exact reasons Longhorn described. The cost of rebuild kits, machine work, motor mounts, and such are item per item more expensive with the BB. I'm hoping with what I can sell from the BB setup I can get myself a good start into a nice 350. I just want to make sure I'm not over simpifying the process.

02-12-2007, 10:51 AM	#6
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,679	Re: Engine Mount - BB to SB Yo do not have to chnge anything as far as mounts go. Using the big block towers for your small block will keep the trans in the same place. If you do this, it will be easier to use a later model bracket setup and the long water pump with the big block shroud. You can even go to a cleaner sepentine setup if the budget allows

02-15-2007, 07:44 PM	#7
PartyPooper Registered User Join Date: Nov 2006 Location: Yorba Linda CA Posts: 22	Re: Engine Mount - BB to SB As most newcomers do, first let me apologize for my ignorance... Would this be the proper mount to use on the BB tower (it's from the Truckshop catalog in Orange CA)?

02-15-2007, 08:33 PM	#8
corn Registered User Join Date: Dec 2003 Location: here Posts: 5,789	Re: Engine Mount - BB to SB I had a 350 in my big block truck for a while. Took the mounts off the 396 & bolted them on the 350. Dropped on the bb towers like it was made for it. I had no issues at all. Did have headers though so not sure on manifolds but I doubt they would be a problem either... Last edited by corn; 10-10-2009 at 12:20 PM.



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