Dennis, two things for you.
Alternators built to look like dynamos are available from Racemettle at
www.racemettleltd.co.uk They are based on the design of a Lucas dynamo and advertised as suiting TRs, Morgans etc. so they should be suitably powerful. I suspect they arent cheap though.
Thought nomber two is that there is a gentleman in the club with a blue Pininfarina coupe which is much modified including an alternator. It also has air conditioning fitted. I think he is a retired engineer so if somone can furnish his name I am sure he would be delighted to give you all the details.
I hope this helps. Let us know how you get on.
Happy Lancia-ing
Frank