Lycoming Service Instruction No. 1255 (dated), 4 August 1972 -Thermostatic Oil Cooler Bypass Valve Replacement
Lycoming Service Bulletin No . 355 (dated) , 4 August 1972 – Alternator Fan Replacement (Prestilite Bulletin No. ASM-8)
Avco Lycoming Service Bulletin No . 365 (dated), 1 June 1973 – Bendix Magneto Conversion to Incorporate Flexible Drive