Ok, I just saw the pics.
100% an AC Autokraft. Body and chassis both, looks to be possibly one of the special order cars that Brian did or modified MKIV with motor likely planted in US as it avoided DOT as a regular MKIV. We all know these are not hard to change if indeed its started as a MKIV. I let the poster know where to look for AK# on frame assuming there is nothing on footbox as the owner has a tall tail to live up to.
There is both MKIV/MKIII charatcer on most of these cars as very few were MKIII alone. More pics I could narrow further but the stories are BS, its not left over 60's AC anything. Sorry.... Its a genuine AC just from 80's, still real just not Shelby connection. I always say that all Shelby's were AC's however not AC's were Shelby's.
Myth busted, its a AC Autokraft roller sent to US with some weird mods on the lights, there were two pictures that show a normal headlamp and one with a mod, not sure which was the most recent?? That will not help the value.
Nice car, bad story!