yeah on the 69 Shelbys they shimmed the fenders,wasn't very prety .i was able to bend the flap up on my 69 and do away with the shims completly.it is usualy only a 1/16 inch at the most.
I've since found out there's a guy 2 minutes away from me (literally) who make what are touted as fabulous GT350 hoods (and a couple of other types). He is in the business of making fg playground equipment and does hoods on the side. Supposed to be excellent. Not $300 though..he charges $650 for them.
As a side note, I've heard lots of different pros and cons about using a steel framed hood vs an all glass hood. Our local Mustang shop owner says steel is absolutely the way to go. He has had no issues with separation etc and says that without steel, the all glass hoods will slowly creep and bow in different places over time.
The guy close to me who makes them used to do them steel frame but doesn't like using frames from the re-pop hoods. With non-rusty, original donor hoods becoming more rare he says he now does them all glass with kevlar reinforcing and inlaid screw ports etc at the hinge area.
I do have a nice, non-rusty hood which I could use as a donor for a steel framed hood. Not sure which way to go.
I bought, from Tony Branda, a 66 GT350 style hood that's a fiberglass skin with a full steel frame. This is a close reproduction of the early 66 GT350 hood. I went with the steel structure since all the GT350's I've seen with all fiberglass hoods were usually warped. The hood was $500 plus $125 shipping. The hood obviously required prep work but it wasn't excessive. The craftsmanship is of good quality and there was enough thickness in the hood to sand it while still matching the contours of the car. http://www.cobranda.com/gthostc.html
Cheers!
Brent