One nice swap I saw a few years ago involved a Jaguar twin-cam 3.8 Liter inline six in a 53 Chevy pickup.
That's one I originally considered Jerry,ironically Jag motors are more common here than small block Chevys.
You can buy a complete XJ donor vehicle for a few hundred bucks/pounds,the only downside is the RHD steering rack.
The Jag straight six can easily produce as much HP as a decent small block if it's built properly too.
Paul Moffat (moff1959) here on the Stovebolt shoehorned a Jag V12 into his '40.
Now that IS different.
I never got round to measuring one up but I imagine the Jag six will fit if you say you've seen one.
Even better you can use
all the running gear so it will handle more like a Jag,rather than a truck.