1956 Sedan DeVille - Need help

Looking to see if anyone has swapped an older Caddy engine with a newer GM V8, including transmission. We've had about everything rebuilt at one time or another on the original - and it's extremely unreliable. Would like to put a modern powerplant in it, and actually drive it. Any ideas on what engine / trans combo would be the easiest fit would be greatly appreciated.

If you want to stay with Cadillac all the 68-70 engines were great including the turbo 400 transmissions, just a matter of finding the units and adapting them into car. Later engines get into complex electronics. Small block Chevies with corresponding transmissions can be bought new. all this is 12v remember.

If you want to stay with Cadillac all the 68-70 engines were great including the turbo 400 transmissions, just a matter of finding the units and adapting them into car. Later engines get into complex electronics. Small block Chevies with corresponding transmissions can be bought new. all this is 12v remember.

I think I'll look at the small block Chevy engines - maybe a complete crate engine for simplicity. Is the 12 v conversion a big deal to overcome?

Actually you could split the voltage 12v for all engine operations and 6v for the body feed, they make devices to do this.

Your original driveline combo should not be unreliable. It's just a matter of having the work done properly.

I can fully understand how an unreliable vehicle can be frustrating, especially if you have already had lots of work done to it. There should be sources out there who can do the work right. The original Caddy driveline is very straightforward and easy to repair.
A modern driveline will be expensive to buy, expensive to install and will decrease the resale value of your car. However, if you still want reliability, go for a small block Chevy engine, with a carburetor and a THM 700R4 transmission (non computer controlled.

And keep all of the original driveline, just in case the next owner wants it.

Looking to see if anyone has swapped an older Caddy engine with a newer GM V8, including transmission. We've had about everything rebuilt at one time or another on the original - and it's extremely unreliable. Would like to put a modern powerplant in it, and actually drive it. Any ideas on what engine / trans combo would be the easiest fit would be greatly appreciated.
not sure but do have a 1956 Caddy shop manual in my possession thinking about listing it in a auto site to sell has all you need to know on repairs in detail plus in good to excellent condition