First thing's first, WELCOME and WHERE ARE THE PICTURES!! See'n is Believing!!
Sounds like an ambitious project. I thought I saw a Triumph that was sold new with a Ford small block, thought it was late 70's or early 80's. Talked to the owner at a show in Santa Cruz CA, and they are a light and fast car. Didn't ask about the roll and twist of the car though.
What is the target weight and HP of the car?
And how are you going to stiffen up the car after all that hacking and replacing?
Can you keep the convertible top with the mods to the rear of the car?
and one more thing.....
WHERE ARE THE PICTURES!!