jaycoop, According to a search through
GM Partswiki for GM# 1513385, that part number was superseded by GM# 6402752 as listed in the "Part Number Replacements and Supersessions 80TS-RP September 1979" publication. The replacement part is listed with a latest application of Chevy 366 and 427 Big Block engines in 1980-82 School Buses per the "School Bus Chassis Parts Book 82TM-SB-F July 1983".
A further check on the web found an
NOS GM# 6402752 that looks like it might fill your need??? At a very reasonable price too. Since it's a direct replacement for the earlier part number, the dimensions should be right for your application. You can always contact the seller and get them to measure the part and confirm before ordering. Hope this might help you get what you need and not have to modify your sender port. Let us know how this turns out.
