73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: lyndoncp on November 26, 2018, 01:44:12 PM

Title: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: lyndoncp on November 26, 2018, 01:44:12 PM

I am in the middle of putting a BBC in my truck and thought I had better upgrade from the TH350 transmission to a built TH400. I have the transmission built and the input shaft changed in my 208 but now I need to mate them up.
I have a flat crossmember and the tall adapter between my Th350 and the 208 right now. I am having a heck of a time trying to track down a tall adapter for the TH400.

Two part question, would it be easier to just change crossmember than to find the tall adapter? Any ideas who makes an aftermarket adapter?

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: fitz on November 26, 2018, 05:58:21 PM

  Most Military CUCV's ran turbo 400/208's with a flat crossmember & a tall adapter.
These truck is are basically mid 80's chevys with a few Military options.
  Check on craigslist. Lots of guys part these trucks out to get their hands on the front Dana 60 & 14 bolt rear with 4.56 gears with a Detroit locker.
  Where are you located?
  Google Hilbilly Wizard.  He runs a business parting out Military trucks.  I just checked, he is selling the adapters for $210. 

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: lyndoncp on November 26, 2018, 07:12:41 PM

Hey thank you very much for that info, very much appreciated. I actually tried to buy that one off his site but he doesn't ship all the way up to Canada.

I'm actually really close to the border and now that I think of it I know a guy just on the Montana side of the border with a bunch of the military square bodies I may try hitting him up.

I see there is a few on Ebay too but man I'll be into one of those about $350 CAD by the time it ends up at my door.

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: lyndoncp on November 26, 2018, 07:14:57 PM

What do you think about fabbing up a spacer for between the current crossmember and a short adapter??

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: Irish_Alley on December 05, 2018, 05:27:13 PM

wont be too bad if its secured right or even making a new crossmember

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: fitz on December 05, 2018, 09:07:00 PM

Try putting an ad on Craigslist to buy 1.
I sold a turbo 400 bolted to a 208 complete with the flat crossmembet for $250
It was from a running & driving CUCV.
They are out there.

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: lyndoncp on December 23, 2018, 09:26:29 PM

Well here was my solution. Difference in height was exactly 4 inches so I glued a couple 2x2 square tubes together and drilled some holes. Wish me luck!

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: JohnnyPopper on December 25, 2018, 04:57:23 PM

Very Clever!

I would glue the nuts in place and then cap the ends.

What gauge is the 2x2? 

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: lyndoncp on December 25, 2018, 09:12:34 PM

2x2 is 3/16

I like the idea of spotting the nuts in place.. hmmm
when you say cap the ends what do you mean??

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: Irish_Alley on December 26, 2018, 07:09:00 AM

think he means capping the ends of the box tubing so no mud and crap gets in

Title: Re: Tall and short TH400 to NP208 adapter- 1981 Chev Scottsdale K10
Post by: JohnnyPopper on January 02, 2019, 12:54:19 PM

Irish nailed it, close the ends to stay clean and add rigidity.