I found an article from 1973 where John R Rices defends the merits of the bus ministry and lists the largest IFB bus ministries at the time.
- First Baptist Church of Hammond, IN (137 buses)
- Landmark Baptist Temple in Cincinnati, OH (118 buses)
- Thomas Road Baptist Church in Lynchburg, VA (78 buses)
- Gospel Light Baptist in Kernersville, NC (52 buses)
- Beth Haven Baptist Church in Louisville, KY (50 buses)
- Central Baptist in Pomona, CA (46 buses)
- Forrest Hill in Decatur, GA (45 buses)
- Emmanuel Baptist Church in Pontiac, MI (43 buses)
- Highland Park Baptist in Chattanooga, TN (40 buses)
- Westside Assembly of God in Davenport, IA (24 buses)
- Fairhaven Baptist in Chesterton, IN (20 buses)
- Providence Baptist Church in Riverview, FL (15 buses)
- Gospel Light Baptist Church in Walkertown, NC
- Canton Baptist Temple in Canton, OH
- Woodland Baptist Church in Winston-Salem, NC