Karl,
The Volvo P1800 is a great car … had one years ago.
There are a few examples of P1800s with V8 conversions, but I don't know of any 'body kits' as such, where as you suggest the P1800 body be put over a modern frame & V8 drive line.
However ... Below is a link to a good article on P1800s and in Part 4 it talks about a prototype V8 P1800 done by Holman and Moody no less, that was tested by Ford and then shown to Volvo executives in 1964 … makes for some very interesting reading.
Bottom line, there is a lot of cutting and redesign that would go into a engine swap like this into a production car, and would take some serious time and talent … but if done well, would result in one cool little car.
Not sure what the market would be for a V8 Volvo P1800 'kit car' ... but I bet Roger Moore would be interested in one ...
VClassics Interactive