$18,000 for 24 valve Cummins, rebuilt, without the fuel system and new harness, electrical ignition, etc... The fuel injection system is another $2500.
(Summit Racing).
$35,000 for the Holey Grail Cummins 12 valve, (with the upgrades to prevent early engine failure), same fuel injection cost ^^^.
The 454 would be tough-er to swap into a Diesel rig, in my opinion.
It's cheaper, even after you upgrade the engine guts, over Turbo.
I would hesitate to say it is better. Diesel has the torque.
The issue is building Diesel to last. $$$$$$$$$$$$$$$$$$$$$$$$ (That's 25K, unless you rebuild what you have.)
Can supply you with a Mark VI 7.4L Gasoline Engine core.
Standard machine work required, probably around $3500-$4500, not including the core and shipping for my engine.
Any Big Block GM is going to cost you $5K minimum, to build any core. It goes up very easily, very fast.
My short block has 96K and a known good ECM/pigtails, if you want to buy it.
No heads, they are spoken for already.
I can tell you where to source the pin out for the ECM, from a guy on GMT400.com.
I own his document and he has the copyrights, so you'll have to ask him to buy the paperwork to swap to the 7.4L.
You can also use the 0411 ECM with the 7.4L and your transmission. Same guy sells that pin out.
It can be programmed and flashed to any engine/modern transmission OEM configuration, unlike my black box ecm, which is pre-tuned for the 4L80E and may not work for your configuration.
Your tuner might ask you to go stand alone ECM/Trans controller, so he has extra parameters of adjustment. $$$$$$
Wouldn't take much to clean the 7.4L up at the machine.
The issue is you then need to build it stronger than OEM and mod your harness and my ECM or the 0411 ECM.
GM sent out the best 7.4L 99' gas engines right at the limit for the 5 year warranty.
The block is awesome, but the internals are carefully selected to fail on a timeline.
They require upgraded crankshaft and rods to run stronger than 5 years for towing.
It's not a bad option, just a bit of wiring work, that can get tricky and better than stock bottom end.
Worth every penny, if you got the dosh! Cheapest way out.
Finding fuel in remote areas is n longer a problem. You now burn gasoline.
Turbo the 6.2 Detroit is going to run $7500.00-$9500.00 with rebuild, inter-cooler mods and proper tuning.
Probably about the same as the 7.4L option, after everything is included, because of re-wiring. Depending on your skills.
Select a reputable turbo charger and the very best blow off valve and high performance fuel system pump / filter mods.
(Or do it cheap and screw it up).
There's a bunch of guys here who can tell you how to hack the build.
I'm not one of them. The $2000 price difference is the cost of a proper forged Diesel crankshaft, HD rods and heavy duty machine work for the 6.2L.
The price reflects QUALITY Diesel turbo charger components and most of the work performed by you, not a shop.
You could easily spend $15K for a shop to build tune and restore your 6.2L Turbo modified for the work you want, with transmission mods.
$20K would be cheaper than the Cummins and a great investment, if you choose parts wisely.
It would still be worth it. Your truck would be amazing. Very reliable. You would have a seasoned team to repair it.
The Forged Summit kit is entry level. (The cheaper non-forged kits would not even be on my radar).
https://www.summitracing.com/parts/cmb-03-0268/make/chevrolet
Dual stage, which would be excellent for your project, are worth the money.
If you can afford to install a Honeywell dual staged Turbo, do it.
It cost a bit more to tune and you will be very pleased with the performance.
You'll need the custom exhaust manifold to run it. It is still worth it!
Emissions, might be easier to meet with one over the other, so consult a professional Diesel tuner and your machinist first.
They might have the kit you'll want in the database from a previous machine shop build.
Your harness needs to be checked out and improved, but changing it could get messy on a Cummins Swap.
You'll need the extra cash you save, to rebuild your transmission to handle your new turbo 6.2L or 7.4L!
Don't forget your rear differential.
The turbo charger will bring out all the issues with the final drive line and brakes.
I priced the swap for a Dodge 2000 4wd 24 valve to a 12 valve, for eight months.
Researched everywhere.
Swapping to Cummins in your GM, is not really efficient use of your money, from my research.
You want a Cummins, go price a verified excellent Dodge 12 valve Diesel truck, and see what it costs, no mods necessary.
$$$$$$$$$$$$$$ Your talking $65K with crappy interior and bad wheels. And you will still own a Dodge Transmission!
Cough cough cough...
Hope this helps.
It's a great project!
Please post pictures of whatever you decide to build!