Spark Plug
Curtiss-Wright/Marquette (Wright Whirlwind J-5 Series, R-540 Series, GR-540E Series, R-760 Series, R-975 Series, GR-975 Series)
Fairchild Engine (Ranger 6-390 Series, 6-410 Series, 6-440 Series)
Gladden ((Kinner) B-5, B-54 (R-440-1, -3)
C-5, K-5, R-5, R-5 Series 2, R-55, R-56)
Jacobs (L-4 Series, L-5 Series, L-6 Series, R-755 Series)
Menasco (Pirate A-4, B-4, C-4,D-4, M-50, Super Pirate D-4-87, Buccaneer A-6, B-6, B6S, Super Buccaneer C6S-4)
Monocoupe Aeroplane Corp. of America (R-266)
Olson, George Company (Scarab Series, Scarab Jr. Series, Super Scarab Series)
Pigman, American Flyers ((LeBlond) 70-Series, 85-Series, 90-Series, 110 7DF, (Ken Royce) 90 5G, 7F, 7G)
Pratt & Whitney (Wasp Jr. Series, Wasp Series)
Teledyne Continental (A65 Series, C75 Series, C85 Series, C90 Series, C125 Series, C145 Series, E165 Series, E185 Series, E225 Series, O-200 Series, O-300 Series, GO-300 Series, IO-346 Series, IO-360-B, O-470-4, 11, 11B, 11-C1, 11B-C1, 13, 13A, 15A, B, E, G, H, J, K, L, M, N, P, R, S, T, U, B-C1, G-C1, K-C1, L-C1, M-C1, IO-470-A, C, D, E, F, G, H, J, K, L, LO, M, N, P, R, S, T, U, V, VO, L/IO-470-A)
Textron Lycoming (O-235 Series, IO-320 Series, AIO-320 Series, LIO-320 Series, AEIO-320 Series, O-320 Series, O-340 Series, O-360 Series, LO-360 Series, HIO-360-A1A, A1B, B1A, B1B, Series,, O-435-A, C, Series, GO-435-C, D, K, Series, O-540 Series, IO-540 Series, AEIO-540 Series, R680 Series)