360 engine vibration

All the work was done in the USA, I imported it from Texas last year, but I bought it from a dealer who had no history. It was originally a 6 pot with a 904 trans and 7 1/2 diff. Now 360 engine, 727 trans, ford 9 1/2 diff, larger disc brakes and re cambered rear leaf springs. I think it was either a stalled conversions or completed and the did very little miles since conversions. Maybe due to the trans vibrations and propshaft issues the PO may have lost interest?? who knows, but would sure love to get some insight into its history. if you live in the Texas katy area maybe you saw it around as the plates tags are dates Sep 2013