New Old Stock Champion RHB37N Spark Plug New Old Stock Replaced by RHB37E (15072). Sheilded 3/4"-20 Thread, 18mm mounting thread, 13/16" reach, 7/8" hex size. According the Champion Catalog these will fit the following Engines:
Lycoming AEIO-320-E, IO-320-C, -F, LIO-320-C (Long Reach), IO-360-A, IO-360-C1F, IO-360-F (Long Reach), IVO-360, TIO-360-A, -B, AEIO-360-A (Long Reach), TO-360-A1A6D, TO-360-C1A6D, TO-360-E, TO-360-F1A6D, LTO-360-A1A6D, LTO-360-E, VO-435-A, -B (Long Reach), TVO-435-A, -B, -C, -D, -E, -F, -G (Long Reach), O-435-23-25, GO-480-G1, G2 (Long Reach), GSO-480-A, -B (Long Reach), IGSO-480-A (Long Reach) IGO-480-A, O-480-1-3, IO-540-AA, -E, -G, -J, -K, -M, -P, -R, -S, -U, O-540-L3C5D, M1B5D (Long Reach), O-540-9, VO-540-Series, IVO-540 Series (Long Reach), IGO-540-A, -B (Long Reach), TIO-540-A, -C, -E, -F, -G, -H, -J, -K, -N, -R, -S, -T, IGO-540-A, -B, LTIO-540-F, -J, -N, -R, TIO-541-A, -E, TIGO-541-A, -E, IO-580-A, IO-720-A, -B, -C, -D (Long Reach) Teledyne Continental R9A Allison V1710 Franklin 6AS-335-A, B, 6AS-350-A, -A1, 6V335-A1A, A1B, 6VS-335-A, -B Pratt & Whitney R-1830 (Twin Wasp C), R-2000 (Twin Wasp D), R-2800 (Double Wasp) R-2800-97, CA3, CA5, CA15, CA17, CA18, CA19, R-4360 (Wasp Major) Pezetel (WSK) ASZ-621R, (1000 h. p.), P2L-3S (600 h. p.) Wright Whirlwind R-760, R-975 (18mm 13/16 Rch.), Cyclone R-1300, Cyclone R-1820 Series (Except F & HE), Cyclone R-2600 Series, Cyclone R-3350, C18BA, C18BD
