The car's current owner is me. The only info I have on Modern Motor Service is an old phone #, no address.
I talked to a guy who bought the car at 16 in partnership with his brother in Toledo, Ohio in 1978. (wonder how that worked out)? Neither he nor his brother can remember who they bought it from, only that is was a private individual and "you couldn't shift it fast enough" It had a set of 4.88's in it!
Thanks for the lead. I'll post again if anything comes of it.