Swap Help please! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Souths79 · 08-26-2009, 06:41 PM

hey everyone, ive got a 79 Sierra half ton 2wd,factory 350 going to a 454. i changed the frame mounts from the small to the big block type and theyre not even close. the sb type are a closer fit than the bb. frame isnt bent and i dont think im that crazy! i can get the sbc mounts to work but the issue there is the engine sits different and the headers (headman) dont come close to the head at all due to dang near the whole header hitting the frame. is there a such thing as a big block clamshell? i assume the were all the same but thats i where a think the prob is. any help would be apprieciated

b454rat · 08-26-2009, 07:00 PM

Clam shells and mounts are pretty much the same for SB and BB. BB rubbers will be denser to handle the torque from the motor. But there is a difference in clam shells, car to truck are different.

I swapped many a BB where a SB used to be and used the mounts off the SB, bolted up no problem.

AirMale · 08-26-2009, 09:13 PM

sbc mounts work with #2455 hooker headers

Souths79 · 08-27-2009, 06:14 PM

b454rat- i figured the clams where the same but just thought id ask, and the same with the mounts. i can get the SBC mounts to fit with a little work but the BBC ones are at least 3/4 inch off. my biggest pry bar wont move them enough to come close! lol.

Airmale- thanks for the advice. what im working with is headman #69130 which is 2in primaries and a 3in collector

does anyone out there have or dealt with those headers??

08-26-2009, 06:41 PM	#1
Souths79 Registered User Join Date: Aug 2009 Location: King George, Va Posts: 12	Swap Help please! hey everyone, ive got a 79 Sierra half ton 2wd,factory 350 going to a 454. i changed the frame mounts from the small to the big block type and theyre not even close. the sb type are a closer fit than the bb. frame isnt bent and i dont think im that crazy! i can get the sbc mounts to work but the issue there is the engine sits different and the headers (headman) dont come close to the head at all due to dang near the whole header hitting the frame. is there a such thing as a big block clamshell? i assume the were all the same but thats i where a think the prob is. any help would be apprieciated Attached Images

08-26-2009, 09:13 PM	#3
AirMale Senior Member Join Date: Jan 2003 Location: Atlantic City, NJ Posts: 1,073	Re: Swap Help please! sbc mounts work with #2455 hooker headers __________________ 86 SWB 9.0 LITER T-400-OD 4.11 eaton-4/5 drop Best 1/4 12.51 @112mph no traction

08-27-2009, 06:14 PM	#4
Souths79 Registered User Join Date: Aug 2009 Location: King George, Va Posts: 12	Re: Swap Help please! b454rat- i figured the clams where the same but just thought id ask, and the same with the mounts. i can get the SBC mounts to fit with a little work but the BBC ones are at least 3/4 inch off. my biggest pry bar wont move them enough to come close! lol. Airmale- thanks for the advice. what im working with is headman #69130 which is 2in primaries and a 3in collector does anyone out there have or dealt with those headers??

08-26-2009, 07:00 PM	#2
b454rat Senior Member Join Date: May 2004 Location: Binghamton, NY Posts: 3,454	Re: Swap Help please! Clam shells and mounts are pretty much the same for SB and BB. BB rubbers will be denser to handle the torque from the motor. But there is a difference in clam shells, car to truck are different. I swapped many a BB where a SB used to be and used the mounts off the SB, bolted up no problem. __________________ 2000 GMC CCSB 454/4L80 6” lift SAS 1999 Chevy CCSB 454/NV4500 6” lift 1999 GMC Yukon 350/4L60 4" SAS



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