3 on the tree to sm465 conversion questions

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Jamesz

Junior Member
Joined
Sep 12, 2024
Posts
25
Reaction score
20
Location
missouri
First Name
James
Truck Year
1977
Truck Model
c10
Engine Size
350
Correct. Cut the opening so that there is still a 3/4" to 1" flange to attach the new trans hump. You can simply use self tappers, or drill larger holes in the base flange and use threaded j-clips, or install nutserts in the base flange for bolts to thread into. Having the removable cover is super handy too.
Gotcha! last night I ordered the cover from Auto Metal Direct so I will see when it gets here.
 

Jamesz

Junior Member
Joined
Sep 12, 2024
Posts
25
Reaction score
20
Location
missouri
First Name
James
Truck Year
1977
Truck Model
c10
Engine Size
350
Correct. Cut the opening so that there is still a 3/4" to 1" flange to attach the new trans hump. You can simply use self tappers, or drill larger holes in the base flange and use threaded j-clips, or install nutserts in the base flange for bolts to thread into. Having the removable cover is super handy too.
One more question. What size bolts do I need for the sm465 to go to the bellhousing? I have been reading different answers. Would you or any others have information/pictures or such to share? Thank you guys so much for the help!
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,614
Reaction score
28,844
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
One more question. What size bolts do I need for the sm465 to go to the bellhousing? I have been reading different answers. Would you or any others have information/pictures or such to share? Thank you guys so much for the help!

Just off memory, they are 1/2" x13 bolts, maybe 1.25 or 1.5 inch long. I can go out and check to be sure in the AM, if I remember.
 

Jamesz

Junior Member
Joined
Sep 12, 2024
Posts
25
Reaction score
20
Location
missouri
First Name
James
Truck Year
1977
Truck Model
c10
Engine Size
350
Just off memory, they are 1/2" x13 bolts, maybe 1.25 or 1.5 inch long. I can go out and check to be sure in the AM, if I remember.
Thank you so much!
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,614
Reaction score
28,844
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
I finally remembered to double check. The bolts are 1.5" long. Course thread, 1/2".
 

Jamesz

Junior Member
Joined
Sep 12, 2024
Posts
25
Reaction score
20
Location
missouri
First Name
James
Truck Year
1977
Truck Model
c10
Engine Size
350
Thanks man! So do I would assume I would need nuts for the bottom two? The bellhousing I got has threads on the top mount holes but none on the bottom. I don't know if I got the wrong one or not.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,614
Reaction score
28,844
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Thanks man! So do I would assume I would need nuts for the bottom two? The bellhousing I got has threads on the top mount holes but none on the bottom. I don't know if I got the wrong one or not.

All four holes should be threaded.
 

Jamesz

Junior Member
Joined
Sep 12, 2024
Posts
25
Reaction score
20
Location
missouri
First Name
James
Truck Year
1977
Truck Model
c10
Engine Size
350
That's weird. I was thinking about it today when I got to the shop so I grabbed some pictures. Do you think I should look into maybe threading these holes?
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach
 

Turbo4whl

Supporting Member
Supporting Member
Joined
Oct 30, 2019
Posts
3,155
Reaction score
7,323
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
That bell housing with open bottom has room to put nuts inside. Older style, will probably only fit the 11" clutch. Advantage is you can use stover style lock nuts. Will not vibrate out.

You must be registered for see images attach
 

Jamesz

Junior Member
Joined
Sep 12, 2024
Posts
25
Reaction score
20
Location
missouri
First Name
James
Truck Year
1977
Truck Model
c10
Engine Size
350
You guys are actual lifesavers. Thank you soo much!
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,614
Reaction score
28,844
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Welp. I had ASSumed that you had the typical aluminum bellhousing that was used in the squarebody trucks. My bad, lol. I'm guessing you will need longer bolts for those bottom holes then, maybe 2". I've never had one of those older bellhousings.
 

Jamesz

Junior Member
Joined
Sep 12, 2024
Posts
25
Reaction score
20
Location
missouri
First Name
James
Truck Year
1977
Truck Model
c10
Engine Size
350
Welp. I had ASSumed that you had the typical aluminum bellhousing that was used in the squarebody trucks. My bad, lol. I'm guessing you will need longer bolts for those bottom holes then, maybe 2". I've never had one of those older bellhousings.
I thought I did too lol. I've never worked on much gm stuff mainly toyota and motorcycles. So I'm not familiar with all the different styles yet. So far so good though! These trucks are super simple.
 

Turbo4whl

Supporting Member
Supporting Member
Joined
Oct 30, 2019
Posts
3,155
Reaction score
7,323
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
You want to measure your bellhousing. Newer style is 6.29" trans flange to engine flange. For many years engines had a single engine mount in the front and used a mount on each side of the trans bell. This is how the many 6 cylinder engines were mounted. Your bell has those mounts.

As more V8s were installed the mounts were switched to 1 mount on the back of the trans and 2 mounts on each side of the engine. You can use that bell as long as the front to back measurement is correct, also the diameter of the rear hole needs match the trans. I think you need 5 1/8" hole.

Squares came with this style bellhousing:

You must be registered for see images attach



This will fit a 12" clutch.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,693
Reaction score
6,875
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
You want to measure your bellhousing. Newer style is 6.29" trans flange to engine flange. For many years engines had a single engine mount in the front and used a mount on each side of the trans bell. This is how the many 6 cylinder engines were mounted. Your bell has those mounts.

As more V8s were installed the mounts were switched to 1 mount on the back of the trans and 2 mounts on each side of the engine. You can use that bell as long as the front to back measurement is correct, also the diameter of the rear hole needs match the trans. I think you need 5 1/8" hole.

Squares came with this style bellhousing:

You must be registered for see images attach



This will fit a 12" clutch.
You must be registered for see images attach

Do you think my spare bellhousing is this one?
 

Turbo4whl

Supporting Member
Supporting Member
Joined
Oct 30, 2019
Posts
3,155
Reaction score
7,323
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
Do you think my spare bellhousing is this one?
I believe there are different diameter trans holes, i.e. the little 3 speed is smaller.

Think about that cast iron bell. You could call it a quick change clutch. Unbolt and slide the trans back. Bar the engine around and remove the pressure plate bolts, it and the disc slide out the bottom. Reach in and slide on the new throw out bearing. Slide the new plate an disc in and install 2 lower bolts loose. Don't need a pilot tool, use the trans. Move it in and push the disc up with 1 or 2 screw drivers and hook it on the trans input shaft. You use that shaft because you can.

Most vehicles 1950 and older vehicles had stick shift trans. Clutch disc was a common wearable item. Maybe the engineers were thinking about the mechanics or were former mechanics. Zoom ahead, engines got more powerful, need for a larger clutch.
 

Latest posts

Forum statistics

Threads
44,414
Posts
956,948
Members
36,734
Latest member
wjh1175
Top