AJS - 347cc OHV (16M) Year: 1948-55, compression ratio 6.3:1. Matchless - 347cc OHV (G3/L) Year: 1948-55, compression ratio 6.3:1. (bore 2.23/32 +.020")
compression height 2.000", piston length 3.7/32 - 1 cylinder (cone head) Pin diameter .7/8. 2 - pistons available (JP Australia).