i don't quite belong in this part of the forum considering i drive a dmax but.... i also have a 1990 short bed chevy (looks just like the black 454SS GM made) but has a 4.3 v6. this was my first truck and i want to do something special with it. i have debated whether or not to put in a corvette LS6 small block 350 or maybe a 12 valve cummins since its prob cheaper and much simpler than a dmax diesel. what do u guys think would be better. i have a feeling going from gas to diesel may cost more and be a lot more involved than sticking with a gas motor.but a turbo diesel blowin smoke out dual striaghts in the back would be pretty slick also. what are your guys thoughts/ opinions?  

Put the Cummins in it!!  It will run circles around the 350 in fuel mileage and power.  They even can be adapted to a TH400 trans quite easily.  You can also get ve-pumped cummins for next to nothing.  

Cummins for sure. I've been wantin to put a cummins in an older chevy maybe 70's so i think it'd be cool. Let us know what you decide. Anyone know where to get a good used 12V?  

well it currently has a five speed manual in it. How hard would this be and what can i expect to spend on a good ready to run used 12 valve. and what kind of stuff will i need to make a gasser a diesel??  

Check out www.destroked.com, they make adapters.  A good running Cummins is anywhere between $1000 for a VE-pump motor, and $4000 for a 215hp p-pumped engine.  Cool part is, no wiring.  Just starter and that's about it.  

so it doesn't need any wiring??  what else do you know of that would be needed so its at the point of making the truck go??  how easy is 350-500 horses and how much to tweak em. i know they can be screwed with just by the screw for the fuel inhection and bigger injectors etc..  

There is a little wiring involved but it is minimal.  You have the starter, alternator, fuel shut off, and possibly A/C.  I installed a p-pumped into my 95' Ford f-350 powerstroke.  I made my own wiring harness for the fuel shut off and starter.  Had an electrical shop modify the dodge alternator to work with my ford electrical system.  Other than that it was mostly a matter of making everything fit.  Should be fairly similar to what you will have to do.  As for finding an engine i found mine a wrecking yard out of a pickup that had been hit in the rear.  Installed a KDP Pin and some gaskets and performance parts.  Have not had any problems with it for the two years it has had that engine in it.  

how easy would it be to tweak 450 horse out of a mechanical 12 valve  

Yeah, I've seen Cummins swapped into that bodystyle Chevy. Not into a half-ton, but I imagine it's possible.

Check out <u>&lt;strong&gt;this&lt;/strong&gt;</u> link.  

how much do you guys think it would cost to get the engine and get it running to streetable use  

haha i love reading these things. yeah that truck would be cool, but dont do it. theres so many other things to take into consideration when doin a swap like that. for one, the cummins is heavy as hell, so your going to have to completly rebuild the front suspension to hold it, you will also need a new rear end to hold the torque of the motor, also with that much weight in the front the back end will be very unstable. i dont know if you have sentimental value with the chevy but if not, sell it and buy an old 12v dodge, they're cheap, especially now with economy crap goin on. im not bashin your project cuz it would be cool, but its not practical, unless your rolling in money, then yeah go for it. also, getting 450hp out of a 12v, easy.