25/51 5th gearset out of a 94-98 V6 Mustang will give you 0.73 with a 3.35 1st gearset.
There are aftermarket options for an 0.80 gearset, but each were designed to achive that ratio when using a 2.95 1st gearset. If you stick those into a 3.35 gearbox, the effective ratio is close to 0.97