1989 K3500 TH400 to 4L80 Swap (Please tell me if I am missing anything)

[Techson94]

Thanks in advance for help.

Truck is 1989 K3500 crew cab long bed. 454 TBI and (I believe) NP205.

I bought a 1998 4L80 with (I believe) a NP246.

I read the NP205 is superior to NP246 so I want to swap in the 4l80 with Np205.

Its my understanding I need to do the following:
1) ECU for transmission control
2) new drive shaft rear. How about front?
3) move the crossmember back
4) extend gear shift lever 1 inch
5) may extend the trans cooling lines

I know there is adapter for 4l80 and np205 but I it looks like that adapter is only needed for 85 or older np205.

Can anyone confirm my list is good and address the 4l80 to np205?

Thank you

 

[rksjd8420]

GM 4L80E to TH400 NP205 Adapter/Spacer Kit

This is our 4L80E to TH400 Pilot Adapter/Spacer Kit. CNC Machined in House from 6061-T6 Billet Aluminum. This adapter is used when replacing a TH400 with a 4L80E. 1979-1984 TH400 to Fig.8 NP205 will require a 2wd 4L80E. (Short 2wd 6-1/4" Stick-out requires the Output Shaft to be trimmed 1-1/8")...

northwestfab.com

This is all you need for the transmission to transfer case adapter.

 

[Techson94]

GM 4L80E to TH400 NP205 Adapter/Spacer Kit

This is our 4L80E to TH400 Pilot Adapter/Spacer Kit. CNC Machined in House from 6061-T6 Billet Aluminum. This adapter is used when replacing a TH400 with a 4L80E. 1979-1984 TH400 to Fig.8 NP205 will require a 2wd 4L80E. (Short 2wd 6-1/4" Stick-out requires the Output Shaft to be trimmed 1-1/8")...

northwestfab.com

This is all you need for the transmission to transfer case adapter.

Thank you!