Cooper Cobra and Mastercraft Avenger GT(both owned by Cooper)are about the only options left besides BFG for solid white letters.There are a few outline white letters available last time I checked.I sold Cooper Cobras for a 67 Camaro and 74 Nova this week to customers.
BFG's SUCK and surely aren't worth the huge price increase over Cooper.

To my knowledge Goodyear(Dunlop as well) Firestone,and Uniroyal have all discontinued these old solid white letter styles.