1965 GMC engine swap 305v6 to350sb - The 1947 - Present Chevrolet & GMC Truck Message Board Network

moovinmetal · 11-21-2010, 10:10 AM

not sure if this will work but, here it goes. will the 350 v8 mate to the bell housing of the GMC stock3 speed and will the 350/3 speed with HEI sit at right height on the stock bell housing cross member and with this combo will the frame mounted crossmember engine mounts work. Thank you, Jack

oldtrux · 11-21-2010, 11:57 AM

Quote:

Originally Posted by moovinmetal

not sure if this will work but, here it goes. will the 350 v8 mate to the bell housing of the GMC stock3 speed and will the 350/3 speed with HEI sit at right height on the stock bell housing cross member and with this combo will the frame mounted crossmember engine mounts work. Thank you, Jack

does a 350 block have the threaded holes on the drivers side for the mechanical clutch linkage?dan

duallyjams · 11-21-2010, 12:31 PM

305 v6 bell housing will not work on a 350 smblk

mikie 1954 · 11-21-2010, 07:21 PM

YOU will need a differant bellhouseing, one from a chevy v8 pu up to I believe a 68 after that they had a larger center hole.I think some i6 bells would work to but not sure of this. The motor mounts are also differant.AS for the driverside threaded hole , some do some don't you will have to look and see.

**Captainfab** · 11-22-2010, 02:09 AM

As long as you use the Chevy V8/I6 bellhousing and the '63-'66 motor mount brackets, you should be fine. And of course as mentioned your 350 will need the threaded boss for the clutch bellcrank ballstud. You will also need to use exhaust manifolds or headers that will accomodate the clutch bellcrank.

raycow · 11-23-2010, 07:53 PM

The bellhousing center hole changed in 68, so you want one from a 63-67 truck. 6 cylinder and V-8 are the same. If you can't find one, you can use a 68-72 bell, but you will need a spacer ring to take up the difference in diameter.

http://dennymac.com/mod.php?mod=user...103&page_id=54

Ray

**Corts60** · 11-23-2010, 09:13 PM

One thing you will notice as well; the stock GMC bellhousing is where the rear mounts are located. There are no tranny mounts, only on the bell housing so if you swap bellhousings, you will need to get a tranny bracket for the tail cone.

raycow · 11-24-2010, 06:58 AM

All of the Chevy truck bellhousings through 72 have the mounts that sit on the crossmember just like your GMC bellhousing. As long as you use one of those, you will not have to do anything about an additional mount or crossmember for the transmission.

Ray

moovinmetal · 11-25-2010, 01:05 PM

Thank you guys for the help. I am planning on using a goodwrench crate motor out of a 78 chev 4x4 auto. I may have to go back to plan A and install the 350TH and go with stock auto on the column and install the linkage. I was trying to make this an easy engine swap and get the ol boy on the road and swap the tranny later. Winters commin and its takin up shop space but, Im sure im singin to the choir LOL Thanks, Jack

codyshawn1974 · 01-11-2011, 01:30 AM

i just finished this swap myself in a 1963 gmc. had to use engine perches from 1965 chevy, got the bell housing from 1970 3/4 chevy used original clutch stuff. currently swapping out the sm420 and going in with sm465. having to shorten driveshaft 3 1/2 inches in the front section to fit. 3.08 gears are next in line for the beast. even rewired it for later style alternator and hei distribuor without cutting a single wire.

1adam12 · 01-11-2011, 02:19 PM

Could you put in a 350 behind the Sm318 tranny? I have 305v6 thinking bout changing it...So i need a motor with holes on side for linkage also i can use all the linkage....

codyshawn1974 · 01-12-2011, 12:57 PM

Quote:

Originally Posted by 1adam12

Could you put in a 350 behind the Sm318 tranny? I have 305v6 thinking bout changing it...So i need a motor with holes on side for linkage also i can use all the linkage....

i believe your asking if a 350 engine will work with your setup as far as the tranny goes. i think it will. i didn't have any problems with the tranny matching up. as long as you use the clutch assembly that goes with the tranny your using and have a 350 bellhousing with the mounts on it. there is a differance between the car bellhousing and the truck bellhousing. cars have no provision for mounts. truck ones do. and don't try to use the perches from a 67-72 chevy. don't work, sits the engine too high. the clutch z bar is different also. get the one for a v8 truck. it makes a difference. that's all i can think of at the moment. good luck!

codyshawn1974 · 03-08-2011, 11:32 AM

I discovered something new on this swap. the clutch linkage has problems lining up with everything else with the stock units from the 305 v6. the v8 sbc version has the clutch linkage on a different mounting point on the frame rail. i had to use an angle grinder with a 3" cutoff wheel to cut off the rivits holding the bracket in place. my setup came off of a 1966 chevy duelly 327 sm420 (4 speed). i simply bolted the new bracket into place on my frame rail in the stock position of the 327, which is a little bit further forward on the rail. there is another hole already drilled in mine and was very easy to relocate the clutch linkage. now i have no binding, no clatter or loose feeling either. it did make a difference inside the bellhousing as well. the clutch engages with a better feel than before.

11-21-2010, 10:10 AM	#1
moovinmetal Registered User Join Date: Sep 2010 Location: Montgomery City Mo Posts: 13	1965 GMC engine swap 305v6 to350sb not sure if this will work but, here it goes. will the 350 v8 mate to the bell housing of the GMC stock3 speed and will the 350/3 speed with HEI sit at right height on the stock bell housing cross member and with this combo will the frame mounted crossmember engine mounts work. Thank you, Jack

11-21-2010, 12:31 PM	#3
duallyjams Registered User Join Date: May 2007 Location: Deale Md Posts: 4,663	Re: 1965 GMC engine swap 305v6 to350sb 305 v6 bell housing will not work on a 350 smblk __________________ James 63 GMC V6 4speed carryall 65 chevy swb bbw V8 auto 68 K20 327/4 speed, buddy buckets 2002 GMC CC Dually Duramax 64 GMC lwb 3/4 V6 4speed SOLD 66 GMC swb bbw buddy buckets SOLD IG duallyjams The only thing that stays the same is constant change!

11-21-2010, 07:21 PM	#4
mikie 1954 Registered User Join Date: May 2009 Location: caliente ca. Posts: 297	Re: 1965 GMC engine swap 305v6 to350sb YOU will need a differant bellhouseing, one from a chevy v8 pu up to I believe a 68 after that they had a larger center hole.I think some i6 bells would work to but not sure of this. The motor mounts are also differant.AS for the driverside threaded hole , some do some don't you will have to look and see.

11-22-2010, 02:09 AM	#5
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: 1965 GMC engine swap 305v6 to350sb As long as you use the Chevy V8/I6 bellhousing and the '63-'66 motor mount brackets, you should be fine. And of course as mentioned your 350 will need the threaded boss for the clutch bellcrank ballstud. You will also need to use exhaust manifolds or headers that will accomodate the clutch bellcrank. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

11-23-2010, 07:53 PM	#6
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: 1965 GMC engine swap 305v6 to350sb The bellhousing center hole changed in 68, so you want one from a 63-67 truck. 6 cylinder and V-8 are the same. If you can't find one, you can use a 68-72 bell, but you will need a spacer ring to take up the difference in diameter. http://dennymac.com/mod.php?mod=user...103&page_id=54 Ray __________________ Live more responsibly. Eat lower on the food chain. Eat vegetarians. Last edited by raycow; 11-23-2010 at 07:54 PM.

11-23-2010, 09:13 PM	#7
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,697	Re: 1965 GMC engine swap 305v6 to350sb One thing you will notice as well; the stock GMC bellhousing is where the rear mounts are located. There are no tranny mounts, only on the bell housing so if you swap bellhousings, you will need to get a tranny bracket for the tail cone. __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/showthread.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 73 Chevy C20(Daily)http://67-72chevytrucks.com/vboard/s...d.php?t=852767 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(sold)

11-24-2010, 06:58 AM	#8
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: 1965 GMC engine swap 305v6 to350sb All of the Chevy truck bellhousings through 72 have the mounts that sit on the crossmember just like your GMC bellhousing. As long as you use one of those, you will not have to do anything about an additional mount or crossmember for the transmission. Ray __________________ Live more responsibly. Eat lower on the food chain. Eat vegetarians. Last edited by raycow; 11-24-2010 at 07:03 AM.

11-25-2010, 01:05 PM	#9
moovinmetal Registered User Join Date: Sep 2010 Location: Montgomery City Mo Posts: 13	Re: 1965 GMC engine swap 305v6 to350sb Thank you guys for the help. I am planning on using a goodwrench crate motor out of a 78 chev 4x4 auto. I may have to go back to plan A and install the 350TH and go with stock auto on the column and install the linkage. I was trying to make this an easy engine swap and get the ol boy on the road and swap the tranny later. Winters commin and its takin up shop space but, Im sure im singin to the choir LOL Thanks, Jack

01-11-2011, 01:30 AM	#10
codyshawn1974 Registered User Join Date: Dec 2010 Location: norman,ok Posts: 39	Re: 1965 GMC engine swap 305v6 to350sb i just finished this swap myself in a 1963 gmc. had to use engine perches from 1965 chevy, got the bell housing from 1970 3/4 chevy used original clutch stuff. currently swapping out the sm420 and going in with sm465. having to shorten driveshaft 3 1/2 inches in the front section to fit. 3.08 gears are next in line for the beast. even rewired it for later style alternator and hei distribuor without cutting a single wire.

01-11-2011, 02:19 PM	#11
1adam12 Registered User Join Date: Apr 2010 Location: Stockton ca Posts: 126	Re: 1965 GMC engine swap 305v6 to350sb Could you put in a 350 behind the Sm318 tranny? I have 305v6 thinking bout changing it...So i need a motor with holes on side for linkage also i can use all the linkage....

03-08-2011, 11:32 AM	#13
codyshawn1974 Registered User Join Date: Dec 2010 Location: norman,ok Posts: 39	Re: 1965 GMC engine swap 305v6 to350sb I discovered something new on this swap. the clutch linkage has problems lining up with everything else with the stock units from the 305 v6. the v8 sbc version has the clutch linkage on a different mounting point on the frame rail. i had to use an angle grinder with a 3" cutoff wheel to cut off the rivits holding the bracket in place. my setup came off of a 1966 chevy duelly 327 sm420 (4 speed). i simply bolted the new bracket into place on my frame rail in the stock position of the 327, which is a little bit further forward on the rail. there is another hole already drilled in mine and was very easy to relocate the clutch linkage. now i have no binding, no clatter or loose feeling either. it did make a difference inside the bellhousing as well. the clutch engages with a better feel than before.



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