Grable's Dart has been repaired, and was racing in the TransAm class at last year's Monterey Reunion.
There were semi-production/homologation rules in TA; for instance '67 Mustangs were not allowed rear disc brakes. By '68, they were homologated.
For many years, the Vintage TA cars were allowed a pretty wide interpretation: for example, the ex-Penske ex-Woods '69 Camaro still had the flared fenders & quarters that Jerry Schwartz put on it at Woods' when later SCCA rules allowed wider tracks, and it ran that way for many years. The Vintage rules have since tightened up, and those flares were cut off & replaced with '69-period-correct panels. Same organization required rear drums on the '67 Shelby Mustang we ran at Monterey last year.