73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Jon87V20 on May 20, 2010, 03:26:16 pm

Title: NP203 Question
Post by: Jon87V20 on May 20, 2010, 03:26:16 pm

Sorry if this is a re-post. I did some searching and looking around on here but didn't really come up with much. I have a '79 K15 with a NP203, 350 and a TH350. A while back, a friend of mine was telling me that you can't swap the TH350 out for a TH400 with the NP203. I was wondering if this was true and why? Thanks!

Title: Re: NP203 Question
Post by: Irish_Alley on May 21, 2010, 02:53:31 pm

The th350 has a 27 spline output shaft the 400 has 32. You can make it work just need adapter

Title: Re: NP203 Question
Post by: Jon87V20 on May 23, 2010, 07:50:05 pm

Thanks, Irish. It's good to finally know the truth.

Title: Re: NP203 Question
Post by: gmcsierragrande on June 05, 2010, 07:37:21 pm

Just Chevy Trucks in Maine has used adaptor plates for the TH350/NP203 as well as for the TH400/NP203. Check his site on Ebay. I'm from eastern Canada and went to his shop a few times for hard to get good condition used chevy truck parts.

This guy really knows Chevy GMC trucks! 

Title: Re: NP203 Question
Post by: malibu795 on June 06, 2010, 07:29:09 am

1st you need the mounting adapter

2nd you need one of 2 things either a 27spline output shaft for the tranny or a 32spline input bearing for the 2 case