JACKPINER INTAKE PORTS

[Rain Man]

I have 2 1973ish JP cylinders side by side and 1 of them has these scallops in the bore just above the intake ports.  The other one has the same scallops, only their extended into the beginning of the intake ports.  I'm not sure what it all means, or if there is a definate advantage  of the ports being extended on that 1 cylinder.
 any comments, suggestions ??
Thanks

Raymond
 Down East Pentons

[Rain Man]

400+ Penton enthusiasts on this web site and not 1 of you know anything about the Jackpiner ports ??  cmon, give me a break

Raymond
 Down East Pentons

[Merlin]

...........the first cylinder is in original piston port configuration,the second had a reed..........