I have a dream of taking a classic car body and retrofitting it with today’s superior technology. For example, taking a '58 de ville frame and giving it a modern diesel engine, A/C, and other such modern gadgets to get today modern comforts. Now I know that many would consider what I want to to as an abomination, but getting past that how difficult is it to do such things. Can I use modern systems with relatively mild modifications (things that take hard work but don’t need a mechanical engineering degree) or would the systems just not function in the older frame. If the latter is the case, why? By the way, this is still just a dream right now so don’t worry about me making bionic car just yet.
Google ‘resto-mod’, what you propose is very popular. As for an engine, there are now ‘crate’ engines that work with fuel injection and catalytic converters.
All depends on $$$$$, of course.
Pick up “Street Rodder” and “Hot Rodder” magazines. They’ll have lots of advertisements from companies that make parts and systems to do exactly what you want. Visit those websites for a real treat. You can even buy entire new frames or rolling chassis for classic cars. For that matter, you can even buy brand new replica bodies! And even bolt-on independant suspension systems front & rear for classic chassis.
The one wrinkle is that you mention a diesel. That will be a bit more difficult. Are you wanting to buy ‘modern’ systems off of junked cars and fit them to the classic body? More difficult than buying the systems described by TSMB above, but doable. The biggest problem with that approach is getting all the electronic engine/transmission controls to work.
Don’t forget to check with your state DMV and see how THEY feel about licensing and titling your creation…The fantasy that you live in a “free country” can come to an abrupt end…Before you achieve Nirvana, you will have spent a lot of money…
You just missed the Back to the 50’s event in St. Paul. 11,700 cars and the people that worked on them, plus the vendors that sell the stuff. They would be great ones to talk to. Next year its June 21. One 55 Chevy though had a $150,000 put into it so depends on your budget.
One way to do it is buy wrecked car of the base you want. Then slip the old body of choice on it. This has been done with an old Cuda body put on a new Cuda. Not for most DIYer’s
I think a front wheel drive Toyota Corolla manual xmission fuel injected power train in a 1964 1/2 Ford Mustang body would be a fantastic car. I’d eliminate the Mustang’s rear axel completely to cut down on weight. The front axels would just be the Toyota CV jointed half-shafts modified to fit and the standard Toyota wheel bearing setup and disc brakes for the front. Not sure what I’d do with the steering. Since I’ll never do this, I guess it doesn’t matter … lol …
There’s a fellow I know, in his spare time as a hobby he soups up and spiffies 70’s and 80’s Toyota Corollas and sells them as vintage cars. He gets some pretty impressive results.
Some people might very well hunt down the person that converted a 64.5 Stang to a Corolla drivetrain. . . 
I have a '62 Thunderbird that I’m planning to put a modern 4.6L engine into. This car will be a resto-mod with modern A/C, drivetrain (except for the rebuilt '62 9-inch rear end), modern disc brakes on all four corners, and a modern stereo. But, I plan on restoring the body and interior to original looks. I’ve sourced all the parts I need, just need to come up with the money to buy them. The drivetrain decision was easy once a knowledgeable friend let me know that the original Ford 390 big block that needed rebuilding would get you 9 MPG on a good day!
BTW, for a Diesel swap, here is a decent article on swapping a Cummings truck diesel into a '96 GMC. Putting something like that into a '53 Caddy should be very similar.
Here’s a site that provides the hardware to fit an Isuzu diesel to a Chevy or Ford transmission.
http://www.isuzudieselswapper.com/
It might not be a good fit for a 1950s Cadillac, but there are a lot of cars or trucks that this might work well in.
I see a bunch of 1964-65 Mustangs setting in driveways @shadowfax, dirty and rusted and never driven for years on end. Might as well have a Corolla power train, shined up, and be driven daily to the grocery store as to sit in the driveway and looking so sad for such a good looking design, that’s my thinking … the early Mustang is the only car I’ve seen that looks like it is moving even when it is parked. And the look has never been duplicated.
The only thing I will add to this is that problems will crop up that are not even on the horizon yet and it will cost more than you figured it would.
George, you’re right, there are LOTS of Mustangs in need of work, and something out of the ordinary would be neat. Go to a car show and all the stock and resto mods get a little boring.
But a diesel truck engine wouldn’t do much for me, but that’s me…
Knuckles, there are people who will pay you serious money for that 390 engine just the way it is…A decent 390 will deliver 14-18 MPG depending on your right foot…
A diesel in a classic Caddy just doesn’t work…Now one of those V-10 Ford truck engines, jazzed up a little, now THAT would work!
I’m a purist so the thought of dumping the 390 (a way underrated engine with a bad underserved rap IMO) in a '62 T-Bird makes me cringe a bit.
Regarding those diesels, a year or so ago Car Craft I think it was did a story about a 70 or 71 Chevelle into which a guy had dropped a late model turbocharged diesel. That thing was churning out about 1100 foot pounds of torque and getting 38 MPG.
No doubt the car would get some strange looks while rattling away at the traffic lights… 
Lots of people go the other way around, putting an old body on a new frame. Many old truck people, for instance, put S10 guts under old 50’s truck bodies. Remember that old frames are not boxed so may not be able to handle the torque, depending on what you put in there. The poor old frame could twist like a pretzel on race day, if it isn’t stiff enough.
If you use the old frame, you may need to box the frame, change the steering, complete new drive train, etc. From what i hear, it is sometimes easier to go the other way around - and ‘easier’ is just relative. To make stuff fit between technology 50 years removed is a job and a half.
I like originality so it isn’t my thing but do understand it is a pile of work. You got props from me if you can pull it off. Walk around car shows and ask the hot rodders how they did it. You’ll get a thousand ideas in one afternoon, no doubt.
@GeorgeSanJose - Don’t get me wrong. I’m not one of the people who would come after you for doing it. I’m all for modding cars - 2 of my 3 cars are extensively modified already, after all.
But there are certain circles where you wouldn’t want to pop the hood and show off your engine if you did it
Yeah, what shadowfax says is very true.
Of course, there are circles that frown on you driving a car that’s totally unrestored and original as well. Lots of them think that cars are supposed to be spit shined to a near perfect showroom quality finish. They are likely the same people that think vintage Air Cooled VW bugs aren’t collector cars and don’t belong at car shows somehow. They also tend to be the same people that have a mechanic on speed dial and have cool garages with vintage oil signs hanging up but with no evidence of oil spills on the floor, neatly arranged toolboxes with no dings on any of the tools, engines cleaned weekly with q-tips, etc.
Not that there’s anything wrong with that…
If is your car - do what you want with it. You can’t please everybody so just have fun with it.