Re: would it be hard to switch the 2 stromberg carbs in a tr6 to holley carbs, or fuel in jection?

You would be a lot better off trying to convert to Webbers. I am sure if you poke around on the net, you could find a company (possibly in the UK) that will sell a conversion kit. You could also go really wild and try to find the mechanical fuel injection system off of a TR-5 (never sold in the US) or a UK spec TR6. If you are the adventurous sort you could adopt one of the aftermarket fuel injection systems to the TR6 engine (see below).

But really why do you want to do this? Why not rebuild the Strombergs? If they are properly adjusted and synchronized, the car will run just fine. I lived with them on a Jensen-Healey. They are a marvel of British over-engineering and can consume countless hours of quality time.

See:

This is my favorite site - still looks like strombergs, but its not..... PI = Petrol Injection, same as FI for us Ed