I can vouch for Hagerty paying my claim on a "modified vehicle", not a total loss, but several thousands in damage, no issues, check cut in full for the estimated repair damages..... I know of 2 other member here on Moparts besides myself that have had claims for damage paid by Hagerty for modified vehicles, in fact one is a heavily modified custom, again no issues from Hagerty for either policy holder

When I was looking for insurance on my '72 big-block Dart, I applied through a couple of the big-name collector companies and sent pics. Neither would consider my modified car as soon as they heard the word "nitrous". One actually asked me to explain what was the blue tank [nitrous] and the aluminum box [fuel cell] in the trunk. I informed them and was promptly declined. My final message was that if they didn't know what those items were, perhaps they should not be insuring hot rods...

Anyhow, Heacock Classic (their underwriter is AMIG, American Modern Insurance Group) had no problem with my 451, 4-speed or the N 2 O... They just charged a slightly higher rate for "Highly Modified" instead of "Modified" class.