I totally see your point. Our local car shows are small enough that they can't really break out different categories of cars beyond 'Stock' and 'Modified' for various year classes (typically 'X0 to 'X9 periods). My Jeep is one of 3 4x4s in our car shows, but competes in the '80-'89 Modified class. Up until last year, it was the '80-Present class. There's no way I could compete with a 2-yr-old Vortec Supercharged Z06 'Vette - so it was a little disappointing. Especially seeing so many absolutely awesome '50s, '60s, and '70s hot rods and muscle cars vying for the same trophy in their class. They finally got a clue and broke out the Mustangs, Camaros, and 'Vettes into their own classes because of so many of them at the show.
OK - that's not really the same thing, but it's the principle. Why is your awesome unrestored Sprint competing against a 30 year newer car that's been garaged the whole time (while yours has been driven and enjoyed)? Seems a little unfair to me as well.
One thing I'm pretty sure of after reading your comments, is that I sincerely doubt my Mach 1 would be welcome to an MCA event with the things I have planned for it... especially if they saw all my 'resurrection' pictures and learned of the front clip swap.