Quickitty,
I would say keep the one that you want and sell the other one -- and sell the Series III E-Type and go out and buy a 1970 Challenger 340 Shaker hood 4 speed convertible..... The E-Type can only hold two people, and it is only a 5.3L V-12 anyway -- and being a 74 it has the ungainly front & rear over riders mounted on the bumpers. Anyway, if you really like the Jag I do get it, I just would have trouble bringing it back to a stock motor as I know the trouble with them, and the limited power that they can produce in stock form. That's why I said go out and get a 70 Challenger convertible. You should be able to get a numbers matching car for around $80,000 -- and these will go up in value more than the Jag, IMHO.
Anyway, whatever you do -- have fun and enjoy.
Mark