Thanks so far guys. I don't hold much fear about heads/gaskets. Only trouble I've had in that respect so far is my own fault running insufficient coolant, just topping up too much with water and having a head eaten away behind #6.

Good thought there re using the standard box, though 4 speed would be nicer for cruising speeds. Most B/Ws run a common case to bellhousing pattern, so that might just work using an earlier 35/40 bellhousing. Something worth investigating.

Could even retro things further...... the Jag is a S2, carby model, so maybe an EA CFI manifold, + XF Weber (or aftermarket 4BBL?) and early dizzy. Would complicate wiring a lot less. Rid the setup of all computer nonsense then.

Though the bottom line is using what I have already available, keeping costs down.