Six to Eight swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

houghda · 06-14-2008, 07:59 AM

My neighbor has a 67 GMC 3/4 ton with the straight six and a stick. We have a Small Block 350 to put in it. I have done this afew times, but always added an automatic. He wants to keep the stick. Will we need to change the bellhousing? Will the SBC motor mounts hit holes already in the cradle? My first truck so I appreciate the info plus any tips. Looks easier than my 55 Wagon was?

caminokid · 06-14-2008, 08:41 AM

You dont have to change the bellhousing. That I know for sure. Someone else will chime in with the rest of the details.

**michael bustamante** · 06-14-2008, 10:43 AM

watch your clearance of the firewall vs. distributer if your going HEI.

houghda · 06-14-2008, 12:27 PM

WOW, thanks for the good news on the BH!
Funny I had completely overlooked/forgotton about the HEI clearance issue.

Super-Dave · 06-14-2008, 12:30 PM

You need to find the V8 mounts that go to the frame. And move the alternator wire to other side if your six is opposite the 8. .Im in the middle of doing mine right now to.

subalternnavert · 06-14-2008, 12:42 PM

Also remember, there are several companies that make bell housings for the SB that will let you run just about any tranny you want and keep the mechanical linkage. You have to be careful, cause the stock bell housing is smaller than later trucks (4 11/16 vice 5 1/8 inch)

06-14-2008, 07:59 AM	#1
houghda Registered User Join Date: Jul 2007 Location: Maryland Posts: 12	Six to Eight swap My neighbor has a 67 GMC 3/4 ton with the straight six and a stick. We have a Small Block 350 to put in it. I have done this afew times, but always added an automatic. He wants to keep the stick. Will we need to change the bellhousing? Will the SBC motor mounts hit holes already in the cradle? My first truck so I appreciate the info plus any tips. Looks easier than my 55 Wagon was?

06-14-2008, 08:41 AM	#2
caminokid Chevy nut Join Date: Jun 2007 Location: Springfield, Illinois Posts: 2,266	Re: Six to Eight swap You dont have to change the bellhousing. That I know for sure. Someone else will chime in with the rest of the details. __________________ 84 Chevy Custom Deluxe 1/2 Ton Named Fade To Black II "Remember kids there is NO replacement for displacement!"

06-14-2008, 10:43 AM	#3
michael bustamante Senior Member Join Date: Sep 2007 Location: Albuquerque NM Posts: 7,862	Re: Six to Eight swap watch your clearance of the firewall vs. distributer if your going HEI. __________________ 1967custom

06-14-2008, 12:27 PM	#4
houghda Registered User Join Date: Jul 2007 Location: Maryland Posts: 12	Re: Six to Eight swap WOW, thanks for the good news on the BH! Funny I had completely overlooked/forgotton about the HEI clearance issue.

06-14-2008, 12:30 PM	#5
Super-Dave Registered User Join Date: Sep 2006 Location: Lompoc, Ca Posts: 128	Re: Six to Eight swap You need to find the V8 mounts that go to the frame. And move the alternator wire to other side if your six is opposite the 8. .Im in the middle of doing mine right now to.

06-14-2008, 12:42 PM	#6
subalternnavert Tire goomba extrordianaire Join Date: Mar 2008 Location: Boiling Springs, PA USA Posts: 132	Re: Six to Eight swap Also remember, there are several companies that make bell housings for the SB that will let you run just about any tranny you want and keep the mechanical linkage. You have to be careful, cause the stock bell housing is smaller than later trucks (4 11/16 vice 5 1/8 inch) __________________ I was told recently by an old friend that the most telling thing he's seen from me is when we were in a bar with other friends reminiscing and mourning lost loves. The others talked of women and fun. I missed my '64 GMC.



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