can you please dump 2 socketed EPROMs ?
as I see its undumped origianal/older Nascar revision (no A letter on IC35 and IC36 labels)
as for maskroms - there no exact analogs I'm affraid. Sega used TSOP48 roms in custom cases, which is ~2mm thinner than common TSOP.
but its possible standard 128Mbit flash roms may fit ? pinout is not different as far as I know.