RE: mach .28
um..........I'd say the 427= .26 and the .28=................ .28
think of a 427 as 4.27 cc like the Savage 4.6 is t measured in cubic centimeters and most other engine companies use cubic inches
Savage 4.6 = .28
Many people argued about this the the LST2 official forum please feel fre to do a search