This question is right up there with who restores windsheild wiper motors and what kind of fuel mileage does a Cummins get.
You'd be better off asking this question on a Shelby Forum; I've been here 15 years and have yet to see this question get answered with any clarity......and it's been asked a lot.
Usually turns into a discussion about opinions on valve stem hole shape, cap color, production rings, early rings, late rings, re-issued rings, warranty rings, re-produced rings, aftermarket rings, who fixes trim rings, he doesn't charge enough, blah, blah blah. I'm not saying this stuff isn't important.........but still no one will answer the question.
I will try to help you though.
Fill in the blank(s):
The best place for 15 inch rallye wheels is__________________
The best place for 1970 tirm rings is______________________
The best place for 1971 trim rings is____________________________
The best place for 1970 center caps is____________________________
The best place for 1971 center caps is_____________________________
Anyone brave enough to fill 'em in?
And for crying out loud Moderators, if the list is filled in with sufficient approval, move it to the archives.