Bellhousing differences

[Nima]

Is there a difference between 67 C20 bell housing with C10 or 68 and later models? If yes, can they be swapped? I am thinking about a transmission upgrade and I don't see much about 67 and/or C20s.
Thanks

[leftybass209]

Yes, they're the same. The frame is the same, as is the engine, body transmission, interior... etc. The differences are things like suspension ball joints, and bushings.

['68OrangeSunshine]

1967 model year was the last year for the SM420 4-speed Muncie transmission. The 420 [and 3-speed Saginaw, iinm] used the GM Bellhousing, p/n 3815891, with a 4-9/16'' opening.
1968 model year and later, used the SM465 4-speed Muncie, and had the GM p/n 3925505 bellhousing, with a 5-1/8'' opening.
So, no. You could have a machinist open up the smaller opening to 5-1/8'', but it might be easier and cheaper to find a '68 and later bellhousing, if you wanted a 465 tranny.
The 465 is longer than the 420, so either the tranny mounts would need to be moved or a 465 crossmember swapped over to use the later transmission.
But now I see you have a ''3-on-the-tree'' 3-speed Saginaw. So it may use the smaller diameter bellhousing even later than 1967...
I know something about 4-speeds, but the Saginaws are a mystery to me.
Sorry to add to the general confusion.
Either bellhousing will mount to an L6 or V8 Chevy engine. There are not different bellhousings per weight class, 10, 20, 30. One exterior size fits all.

[Nima]

Thank you very much.

[Husker]

What tranny you swapping in? I am going to a T5 sometime soon.

Ron

[Nima]

That is were I am heading too. I am doing a lot reading to see what parts I need.

['68OrangeSunshine]

I don't think the T5 uses the older cast iron bellhousings.

[LockDoc]

-
If you haven't already, check this thread out.....

http://67-72chevytrucks.com/vboard/s...d.php?t=438224

LockDoc

[Nima]

Originally Posted by LockDoc

-
If you haven't already, check this thread out.....

http://67-72chevytrucks.com/vboard/s...d.php?t=438224

LockDoc

Yes,I have. It is an excellent thread. Thanks.

[Husker]

Great Stuff here.
Ron
http://lugnutz65chevystepside.weebly...info-page.html

[Mike C]

Originally Posted by '68OrangeSunshine

1
The 465 is longer than the 420, so either the tranny mounts would need to be moved or a 465 crossmember swapped over to use the later transmission.

Both of these transmissions hang off the bellhousing which is where the "rear" mounts are in these trucks.

Length of the trans won't affect mounts, but possibly require driveshaft mods.

['68OrangeSunshine]

Originally Posted by Mike C

Both of these transmissions hang off the bellhousing which is where the "rear" mounts are in these trucks.

Length of the trans won't affect mounts, but possibly require driveshaft mods.

Thanks for clearing that up. I was just thinking out loud.
Personally, I'm happy with the dependable SM465. A buddy had a T5 in his S/10 and we were always pulling that thing out for repair. [Although one time it was his differential that was making noise and the tranny was OK.] So I don't trust manual trannies that use ATF instead of good 'ole 90 weight.
I could be tempted by an A833, if one ever comes my way. But I'm used to the Muncie 4-speed. Hyd clutches are another device that I recall an acquaintance constantly moaning over, too. I've had the '68 Stepside since 1973 and the '71 4x4 Jimmy since 1995, so I'm an old dog, and set in my ways.
[In response to your comment: the 4WD SM465/NP205, does mount to a crossmember on the [K/5] K/1500, but I'd have to crawl under the C/10 to verify if that's true of 2WDs, so I'll just take your word for it.]

[BigTopGT]

Bringing this back from the dead for some advice:

I've got a starter pad broken on th bellhousing in my 67 and have a 68 (on the title) parts truck available.

Broken bellhousing is P/N GM9 3815891

The spare is GM5 3925505

Both trucks had a 3 speed, though the broken one was on the floor and the spare was on the tree.

Can anyone confirm them as interchangeable or do I need a new bellhousing entirely? (pics should be uploading)

Thanks in advance, fellas.

[geezer#99]

They don’t interchange.
Different size opening where the trans input bearing housing fits.
Post #3 has the info for that.

[BigTopGT]

Originally Posted by geezer#99

They don’t interchange.
Different size opening where the trans input bearing housing fits.
Post #3 has the info for that.

Thanks.

I was hoping the fact that I had two 3 speeds that it'd work.

Never easy, is it?

[geezer#99]

There is a way to use a 505 bellhousing with your trans.
Use a spacer ring like this.

https://www.advanceadapters.com/prod...-down-to-4686/