66 Dart GT HT Whatsitgonnabe?

Not sure about the pushrod relocation idea. You may be able to move them, then clean out the hump. There may not be enough material there to do this. Thats why i think the T/A heads were different castings.

Good score by rhe way. Valve guides on these are a press fit, then the hole for the valve stem is machined for proper stem clearance. I would imagine a good machine shop could fix em up for you. Here in the states our machine shops are used to seeing american and foreign. I think all they really need is the specifications it needs to be, and the parts.

A buddy of mine years ago had a 1981 motoguzzi 1000 SP. Had to get the crank balanced for his new rods, and pistons, also needed a valve job on the heads. A local auto machine shop fixed him right up despite never messing with one of those before. He gave em all the specs in metric, and away they went. Everything came back perfect.