[Rapewta]

A Sunbeam Tiger sat in the parking lot (or used to) where I once worked.
It had a Ford 260 ci engine. I think some of them had 289's and some Shelby upgrades.
Besides that one, I never see them so they have got to be very very expensive.
Hard to keep cool in warm weather.
I imagine their are lots of after market upgrades available through the Shelby
avenues.
I haven't checked for a long time but if you don't care about resale and being authentic... and you are a mechanic then check out the replica industry.
You can build one. More reliable than the originals and a lot less expensive.

I did that in 1990 with the AC Cobra and enjoyed 20K miles of fun.
You know the car intimately because you built it.
The Tiger would be a great car to build. Good luck.