Author Topic: auto to 3 speed swap..  (Read 18734 times)

Offline hotrod24

  • Senior Member
  • ****
  • Posts: 1696
Re: auto to 3 speed swap..
« Reply #15 on: November 02, 2011, 10:46:49 am »
Ok i found it!  My 78 I had tore down, I found a picture of the frame and the bracket.  It is the same bolt pattern as my 80 two wheel drive.  So I guess I am good there. Yea I cannot find the holes for the clutch rod.  I cannot find an RPO codes either. 

1980 1/2 ton shortbed project...
1978 pontiac grand prix...

Offline Captkaos

  • OWNER and Administrator
  • Administrator
  • Senior Member
  • *****
  • Posts: 18461
    • http://www.73-87chevytrucks.com
Re: auto to 3 speed swap..
« Reply #16 on: November 02, 2011, 11:46:07 am »
The Auto setup is mounted below the frame with Rivets, the manual setup is mounted above the frame and much further forward than where the auto setup is.  You cannot use one for the other...

This is the clutch bracket:

Offline roger97338

  • Registered Users
  • *
  • Posts: 230
Re: auto to 3 speed swap..
« Reply #17 on: November 03, 2011, 01:52:15 pm »
My 1975 (2wd) was originally a three-on-the-tree, and it has the low hump in the cab.

Offline HAULIN IT

  • Senior Member
  • ****
  • Posts: 1542
Re: auto to 3 speed swap..
« Reply #18 on: November 04, 2011, 09:25:31 pm »
Ok i found it!  My 78 I had tore down, I found a picture of the frame and the bracket.  It is the same bolt pattern as my 80 two wheel drive.  So I guess I am good there. Yea I cannot find the holes for the clutch rod.  I cannot find an RPO codes either. 


Why would this frame have both the clutch z bar bracket & the auto bracket? Both sure appear to be factory rivets.
Hotrod, Tell us about that truck...I see it's a 4x4, but what about other details? Lorne

Offline Captkaos

  • OWNER and Administrator
  • Administrator
  • Senior Member
  • *****
  • Posts: 18461
    • http://www.73-87chevytrucks.com
Re: auto to 3 speed swap..
« Reply #19 on: November 04, 2011, 10:01:39 pm »
The auto bracket looks like bolts to me.  My 1973 (pictured) had the holes for the auto bracket.

Offline hotrod24

  • Senior Member
  • ****
  • Posts: 1696
Re: auto to 3 speed swap..
« Reply #20 on: November 07, 2011, 03:07:23 pm »
I think the 78 i had was a straight drive at one time, So thats why it has both brackets. The auto bracket was bolted but the z bar was riveted to the frame...
1980 1/2 ton shortbed project...
1978 pontiac grand prix...

Offline hotrod24

  • Senior Member
  • ****
  • Posts: 1696
Re: auto to 3 speed swap..
« Reply #21 on: November 08, 2011, 01:31:44 pm »
Ok i found out that my 80 2wd has always been an auto, I found an emission sticker on the core support that said it was.  So that is taken care of.  I just have to find out now how I am going to do this 3 speed swap, like where does the clutch rod come though the firewall.  Would anyone have pics of the hole in the firewall?
1980 1/2 ton shortbed project...
1978 pontiac grand prix...

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: auto to 3 speed swap..
« Reply #22 on: November 08, 2011, 02:04:07 pm »
What do you mean by "3 speed"? Do you mean three on the tree, or do you mean the sm465 4 speed with granny low?
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline hotrod24

  • Senior Member
  • ****
  • Posts: 1696
Re: auto to 3 speed swap..
« Reply #23 on: November 08, 2011, 02:16:19 pm »
Three on the tree...
1980 1/2 ton shortbed project...
1978 pontiac grand prix...

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: auto to 3 speed swap..
« Reply #24 on: November 08, 2011, 02:18:42 pm »
Okay, so you dont need to worry about a high hump or cutting a hole in the floor. I can take some pictures of my clutch rod location, but I dont know if the clut h rod is in the same place on the 3 on the tree as the SM465.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline hotrod24

  • Senior Member
  • ****
  • Posts: 1696
Re: auto to 3 speed swap..
« Reply #25 on: November 08, 2011, 02:22:14 pm »
Thanks man, They should be in the same place...
1980 1/2 ton shortbed project...
1978 pontiac grand prix...

Offline Captkaos

  • OWNER and Administrator
  • Administrator
  • Senior Member
  • *****
  • Posts: 18461
    • http://www.73-87chevytrucks.com
Re: auto to 3 speed swap..
« Reply #26 on: November 08, 2011, 03:03:32 pm »
I am a little confused on what we are still discussing or looking for....

There are only 2 brackets.locations for pickups.  Manual and Auto.  You have both.  Manuals are the same bracket regardless of what is in the truck..  The Auto's are the same for Auto's but I vaguely think the 700R4 has a different version...  I still need to check that though..

If you are using a 3 on the tree muncie, you use the manual bracket...

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: auto to 3 speed swap..
« Reply #27 on: November 08, 2011, 03:24:17 pm »
He is wanting to know where the clutch rod goes through the floor. I should have some pics of it for you tonight.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline hotrod24

  • Senior Member
  • ****
  • Posts: 1696
Re: auto to 3 speed swap..
« Reply #28 on: November 08, 2011, 03:36:21 pm »
Thanks...

He is wanting to know where the clutch rod goes through the floor. I should have some pics of it for you tonight.
1980 1/2 ton shortbed project...
1978 pontiac grand prix...

Offline hotrod24

  • Senior Member
  • ****
  • Posts: 1696
Re: auto to 3 speed swap..
« Reply #29 on: November 08, 2011, 03:53:14 pm »
Yea chris i will be using the manual bracket, But as far as i know i will have to use the auto bracket to. Because of the column linkage...








I am a little confused on what we are still discussing or looking for....

There are only 2 brackets.locations for pickups.  Manual and Auto.  You have both.  Manuals are the same bracket regardless of what is in the truck..  The Auto's are the same for Auto's but I vaguely think the 700R4 has a different version...  I still need to check that though..

If you are using a 3 on the tree muncie, you use the manual bracket...
« Last Edit: November 08, 2011, 03:56:31 pm by hotrod24 »
1980 1/2 ton shortbed project...
1978 pontiac grand prix...