K30 Downgrade to Cummins Project

[Dieselwrencher]

Originally Posted by Vintage Windmills

I decided to roll the dice and try the all aluminum 2.44 thick 4 core off ebay. Its being shipped and now I'm working on figuring out the trans crossmember. Think I'll just build it from scratch or modify the chevy one.

on this cold day I'm putting a list together of things I need to research and figure out.

- Tach- Whats the best way to get a tach on this thing?
- AC compressor mount- needs to be up higher. I could try to locate a medium duty truck water outlet/mount bracket but it may be $400? Otherwise I could maybe buy this
setup but I'm concerned they say the lower water neck needs to point down at 45 degrees. I don't want to do that since that will send it right towards the frame rail.
https://www.dieselconversion.com/hig...l#!prettyPhoto

-Cruise control - whats a good non vacuum option?
-Dmax rear axle springs are so long, I'd have to move the stock saddle fuel tanks. The springs in the truck are 10 leaf and look like they'll be pretty stiff. Perhaps if/when I swap
to the AAM 11.5 I will just get a set of stock K20 rear springs. I have the air lift airbags in the rear for capacity when hauling heavy.
-Fuel system - need to figure out if I should replace/upgrade the tanks or just flush them out. I'd like to run the dual tank setup. Trying to remember if the lift pump on the
engine is enough to draw the fuel or if i need a pump closer to the tank. Can't remember what the dodge gen 1's did. I think they just used the lift pump.

Does your truck have a factory tach currently? On my 72 I haven't gotten my tach done but I am using a dodge pick up sensor from a 92-early 98. I'm also using that style balancer that has 2 extra grooves cut into it so it will pick up the proper pulse for the gm tach. You can then wire the pick up sensor to your truck harness but you have to add a 1k ohm resistor to the pick up sensor harness so the tach will work correctly.

Or you can get a signal conversion box from dakota digital or even off ebay.

AC compressor mount...... Here is a link to a thread that has the part numbers listed in it if you need them. If you go this route and let me know and I'll get you some prices if you'd like.

https://www.ford-trucks.com/forums/1...bracket-2.html

That DCS one does allow you to use your stock dodge alternator and the price isn't horrible. On the lower inlet you could make your own. Make a flat flange that bolts to the new mount and then use 90s and cut/weld to get your angle you need. On my Corvette I cut up a dodge bracket and welded a 90* bend on it and it's been on there since.

I feel this is one of the best cruise control set ups out there. Years ago I put some on semis and they worked great.

http://www.rostra.com/universal-afte...-by-rostra.php

As far as the fuel system goes, you can run your stock stuff and use that stock switch over valve. You don't need another pump other than the lift pump that is on the side of the engine block. The only thing that I don't like about using the dual tank set up is it is kind of small line size if you are running a p pump at volume. At the power levels you're going to be you would be fine though.

As far as the newer leaf spring swaps etc, I'm no help there. I haven't done any on these trucks.

[Vintage Windmills]

Originally Posted by Dieselwrencher

Does your truck have a factory tach currently? On my 72 I haven't gotten my tach done but I am using a dodge pick up sensor from a 92-early 98. I'm also using that style balancer that has 2 extra grooves cut into it so it will pick up the proper pulse for the gm tach. You can then wire the pick up sensor to your truck harness but you have to add a 1k ohm resistor to the pick up sensor harness so the tach will work correctly.

Or you can get a signal conversion box from dakota digital or even off ebay.

Thanks Ryan. Not a factory tach truck. There's a Sunpro tach that was installed for the BBC. It reads pretty high for a diesel. I'm mainly trying to figure out the pick up sensor. It seems I may be able to tap into the alternator rectifier, add a different damper with more grooves, or just add a 4pulse ring like this: http://www.destroked.com/mobile/prod_tach_kits.php Where did you mount your pick up sensor?

Originally Posted by Dieselwrencher

AC compressor mount...... Here is a link to a thread that has the part numbers listed in it if you need them. If you go this route and let me know and I'll get you some prices if you'd like.

https://www.ford-trucks.com/forums/1...bracket-2.html

That DCS one does allow you to use your stock dodge alternator and the price isn't horrible. On the lower inlet you could make your own. Make a flat flange that bolts to the new mount and then use 90s and cut/weld to get your angle you need. On my Corvette I cut up a dodge bracket and welded a 90* bend on it and it's been on there since.

Good reference on the part numbers, I need to compare the options today while looking at where the boost and air intake tubes will run.

[Vintage Windmills]

Pics of the rad. Looks good and box was in good shape and it was well packed. The funny thing is the one mount ear was bent. It must have been bent before being boxed LOL. Shouldn't be a big deal though. The size and quality looks good to me.


I bought a fan off craigs to see if I could fit the mech fan and I can get about 3/4" clearance it seems but I need to mock up grille, intercooler and AC conderser to confirm. The thing I'm not liking is the fan is too low it seems. The tips dip below the core support about 3 or 4 inches.