is this crossmember 6 cyl manual only? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mrhurt73 · 04-08-2021, 03:08 PM

I am in need of finding a transmission crossmember, but i see conflicting info on which ones i could replace it with.
the truck is a 1971 C-10 with straight 6 and 3 speed manual transmission

found a truck with V8 manual transmission and crossmember is in different holes

see the attached pictures i took for reference, any help will greatly be appreciated

and yes it broke the bellhousing, i think its only a 6 cyl bellhousing part also because of starter mounting in bellhousing

**MJN** · 04-08-2021, 03:20 PM

Can't help with the crossmember but the starter was mounted to the bellhousing for manual transmission trucks regardless of engine up to 1973. So that bellhousing mounted starter is not just a six cylinder part.

mrhurt73 · 04-08-2021, 03:22 PM

Quote:

Originally Posted by MJN

Can't help with the crossmember but the starter was mounted to the bellhousing for manual transmission trucks regardless of engine up to 1973. So that bellhousing mounted starter is not just a six cylinder part.

well thats a start, thanks for the info.
hopefully someone knows about crossmember

gmc684x4 · 04-08-2021, 05:01 PM

That bellhousing also has two different hole sizes one for sm420 sm465 has a larger hole

I can not say if crossmember differs
In c10 trucks they moved the v8 further ahead inches frame to a 6 cyl which was in in back set of engine mount holes

**Furno68C20** · 04-08-2021, 05:24 PM

Quote:

Originally Posted by gmc684x4

That bellhousing also has two different hole sizes one for sm420 sm465 has a larger hole

I can not say if crossmember differs
In c10 trucks they moved the v8 further ahead inches frame to a 6 cyl which was in in back set of engine mount holes

Left SM420 Right SM465

That crossmember looks like a 6cyl. I could be wrong. GrumpyOldMan would know

mrhurt73 · 04-08-2021, 05:38 PM

Quote:

Originally Posted by Furno68C20

Left SM420 Right SM465

That crossmember looks like a 6cyl. I could be wrong. GrumpyOldMan would know

the one on the right looks like the one i got. this one is a 3 speed transmission i wonder if i found a SM465 bellhousing would it still work? the bolts should line it up as far a centerline. don't know, just thinking out loud

**LockDoc** · 04-08-2021, 06:17 PM

Quote:

Originally Posted by mrhurt73

I am in need of finding a transmission crossmember, but i see conflicting info on which ones i could replace it with.
the truck is a 1971 C-10 with straight 6 and 3 speed manual transmission

found a truck with V8 manual transmission and crossmember is in different holes

see the attached pictures i took for reference, any help will greatly be appreciated

and yes it broke the bellhousing, i think its only a 6 cyl bellhousing part also because of starter mounting in bellhousing

Read through this thread.

http://www.67-72chevytrucks.com/vboa....php?p=8633251

LockDoc

**'68OrangeSunshine** · 04-08-2021, 07:50 PM

Quote:

Originally Posted by mrhurt73

I am in need of finding a transmission
L6 -only diagonal crossmembercrossmember, but i see conflicting info on which ones i could replace it with.
the truck is a 1971 C-10 with straight 6 and 3 speed manual transmission

found a truck with V8 manual transmission and crossmember is in different holes

see the attached pictures i took for reference, any help will greatly be appreciated

and yes it broke the bellhousing, i think its only a 6 cyl bellhousing part also because of starter mounting in bellhousing

Could be a special L6 292-only crossmember. They were only used on 4x4 trucks with a 292. 250s could be mounted on a conventional crossmember. C/ model trucks didn't need a special crossmember for a 292.

See pix:

**Grumpy old man** · 04-08-2021, 10:04 PM

You have a 6 cylinder manual cross member , You can see in these pictures the V8 cross member mounts further forward in the frame . How did you bend it like that ? you may want to take some X measurements to check if the bent cross member tweaked the frame out of square ?

**69GMC2004** · 04-09-2021, 11:59 PM

That looks like the same crossmember that was in my 292 SM465. Mine was a but straighter though. It mounted in the holes directly in front of the front cab mount.

mrhurt73 · 05-04-2021, 12:02 PM

I found a crossmember and bellhousing while i was in pigeon forge for the spring rod run.
price was higher than it should have been, but its pigeon forge prices. and i was there and it was there. so now its sandblasted and painted, going in frame. and i did check frame, got lucky the old crossmember started to rip at the rivets instead of pulling frame.
thansk everyone for all the info

**Grumpy old man** · 05-04-2021, 12:42 PM

Here are a couple more pictures of the V8 vs 6 trans cross members the V8 is on the left .

The bell housings are different by the size of the hole for the trans , the 67 bell housing is smaller .

**'68OrangeSunshine** · 05-05-2021, 02:06 PM

Bellhousing for the MY '68-later SM 465 has casting numbers: [GM5] 3925505 = 5-1/8'' diameter.
SM420 bellhousing was [GM11] 3815891 = 4-9/16'' dia.

04-08-2021, 03:08 PM	#1
mrhurt73 Registered User Join Date: Aug 2012 Location: clifton forge, va Posts: 261	is this crossmember 6 cyl manual only? I am in need of finding a transmission crossmember, but i see conflicting info on which ones i could replace it with. the truck is a 1971 C-10 with straight 6 and 3 speed manual transmission found a truck with V8 manual transmission and crossmember is in different holes see the attached pictures i took for reference, any help will greatly be appreciated and yes it broke the bellhousing, i think its only a 6 cyl bellhousing part also because of starter mounting in bellhousing Attached Images __________________ My Projects- http://67-72chevytrucks.com/vboard/s...d.php?t=557301 Quest for Hot Rod Power Tour 2013. http://67-72chevytrucks.com/vboard/s...d.php?t=543735 my 85 GMC 2wd to 4wd conversion for the wife.

04-08-2021, 03:20 PM	#2
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,071	Re: is this crossmember 6 cyl manual only? Can't help with the crossmember but the starter was mounted to the bellhousing for manual transmission trucks regardless of engine up to 1973. So that bellhousing mounted starter is not just a six cylinder part. __________________ '51 South Bend Model "9A" '56 Chevy 3600 NAPCO '74 Chevy Cheyenne Super K20-restored on 37's '72 GMC Sierra Custom K2500- in progress '08 GMC Envoy Denali '12 GMC Sierra 2500HD Denali '17 GMC Yukon XL VCCA member #58596 http://www.nohrco.com

04-08-2021, 05:01 PM	#4
gmc684x4 Registered User Join Date: Jul 2012 Location: Whitehorse yukon Posts: 1,218	Re: is this crossmember 6 cyl manual only? That bellhousing also has two different hole sizes one for sm420 sm465 has a larger hole I can not say if crossmember differs In c10 trucks they moved the v8 further ahead inches frame to a 6 cyl which was in in back set of engine mount holes

04-08-2021, 10:04 PM	#9
Grumpy old man Senior Member Join Date: Dec 2013 Location: Gods country East,Tn Posts: 8,545	Re: is this crossmember 6 cyl manual only? You have a 6 cylinder manual cross member , You can see in these pictures the V8 cross member mounts further forward in the frame . How did you bend it like that ? you may want to take some X measurements to check if the bent cross member tweaked the frame out of square ? Attached Images __________________ 1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop

04-09-2021, 11:59 PM	#10
69GMC2004 Active Member Join Date: Nov 2018 Location: SHERWOOD PARK, AB Posts: 113	Re: is this crossmember 6 cyl manual only? That looks like the same crossmember that was in my 292 SM465. Mine was a but straighter though. It mounted in the holes directly in front of the front cab mount.

05-04-2021, 12:02 PM	#11
mrhurt73 Registered User Join Date: Aug 2012 Location: clifton forge, va Posts: 261	Re: is this crossmember 6 cyl manual only? I found a crossmember and bellhousing while i was in pigeon forge for the spring rod run. price was higher than it should have been, but its pigeon forge prices. and i was there and it was there. so now its sandblasted and painted, going in frame. and i did check frame, got lucky the old crossmember started to rip at the rivets instead of pulling frame. thansk everyone for all the info __________________ My Projects- http://67-72chevytrucks.com/vboard/s...d.php?t=557301 Quest for Hot Rod Power Tour 2013. http://67-72chevytrucks.com/vboard/s...d.php?t=543735 my 85 GMC 2wd to 4wd conversion for the wife.

05-04-2021, 12:42 PM	#12
Grumpy old man Senior Member Join Date: Dec 2013 Location: Gods country East,Tn Posts: 8,545	Re: is this crossmember 6 cyl manual only? Here are a couple more pictures of the V8 vs 6 trans cross members the V8 is on the left . The bell housings are different by the size of the hole for the trans , the 67 bell housing is smaller . Attached Images __________________ 1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop

05-05-2021, 02:06 PM	#13
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,563	Re: is this crossmember 6 cyl manual only? Bellhousing for the MY '68-later SM 465 has casting numbers: [GM5] 3925505 = 5-1/8'' diameter. SM420 bellhousing was [GM11] 3815891 = 4-9/16'' dia. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.



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