Don't let me turn you off, but do keep your eyes open mate.
The big issue I have with building a competitive Classic is the huge amount of custom work required by professionals. I've seen it a lot, a bloke spends a fortune building a fantastic old car with heaps of good mods etc, only for it to be damaged to a point of questionable repair.
It happened to a mate of mine at Adelaide a couple of years ago. Spent well over $100k on an early RX7, custom 5 link, awesome cage, Hollinger box, hundreds of lovely custom things, only to throw if down a bank hard and wrote it off.
He sold all the bits be could and walked away. Very sad.
Thats one reason I choose to race a relatively easily replaced car, just find another and cage it up....... That's just my point of view though.