89 Suburban swap ??

[1leg]

Looking to swap the SBC in my 89 suburban 4wd to a diesel. Reason for the swap, need more towing power, and MPG. I know I want a Cummins 4 or 6 cylinders.
I want Big block power, 250+ hp, and 350+ FTlbs . I’m ok with towing at 55mph as long as it will do it going up hill too.
MPG, 15-20 towing
Can I keep my TH400 trans?(currently has 4:10 gears) What adapter will I need if so? Do you think a gear vender overdrive will work?
If I can’t use the th400 then I’ll look for a complete 4wd truck and do a complete drivetrain swap. Must be Automatic.
What year truck should I be looking for? I want as little electronics/computers as possible for this swap. I want the engine to stay as stock as possible (Stock turbo). The plan will be to refresh whatever motor I buy before the swap.
Thanks guys.

 

[dezl]

I would try and keep the th400 behind it unless you plan on using a 4bt. also depending on what your towing I think you mileage requests are a bit unrealistic.

If I was you I would looked for a wrecked 2gen cummins. It will have everything you need.

 

[PackRat]

No O/D, & 4.11 gears? 55mph will probably be close to governed out.

Also, if there is a difference(I can't say, for certain), you might look into picking up a set of torsion bars from a 1-ton. There is a significant difference in weight, from a mouse motor to a Cummins.

 

[cat3176]

The turbo 400 should last just fine. If you are trying to stay away from computer controlled stuff I would go with the first gen trucks, the intercooler may be a tight fit if you get one out of 1991.5-1993 but it has been done before. If I remember correctly the non intercooled engines were from 1989-1991.5 but I may be wrong, other members on here would know for certain. I would look into a set of leaf springs out of a 1-ton. The transfer case would be my next concern considering the 208 wasn't the strongest chevy ever made but it might last just fine. There are two good choices I would look into for transfer cases. I would use either the np203 chain driven or a divorced np205 gear driven, the 205 is a bit noisy but in my opinion the strongest of the two. That way if you ran the 205 you could put whatever style trans in as long as the u-joint at the transfer case matched the yoke. But if you were to use the np203 all you would have to find is the adapter for the 400. I'm glad to see someone else thinking on doing this swap because I would love to do this to my 1990 burban. This is just my .2 cents. Hope your planing and project goes well.

 

[u2slow]

There is NO joy with a diesel and TH400.

I would find a 4L80E from a 6.2L or a non-turbo 6.5L - these had a standalone controller.