THat barrel is kosher. fitting a spacer to anything dont make it illegal as pre 70 guys fitted spacer ( neil keen for one) its an A looking motor from the out side so its within the rules full stop. YOU guys that are matching up 1980's ignitions, folowing year clutch actuators and so on, are a bit cheaky trying to doubt out out an internal port job on a motor, as its not bolt on power like a ign is, specillay if you going from points to electronic.
I dont know why some guys in the US use the 79 piston, it must be Real cheap, cause they sell mx 250 and so on piston and Wisecos for $30 and the kits for $50 on ebay all the time. I thnk they went down this path before the internet made parts easy to find. The piston change has no real performane advantange if anything its a pain in the arse as it locks you into that piston, the only exception to that would be on the 360, but then again i used a cheap iron liner and a cheap MX 360 piston, peice of piss and looks correct from any outside angle and could have been done in the day.
