X-heads vs J-heads: what's the difference??

E-Man,

In 1971 {actually late-1970 Castings} Chrysler used the #3418915 'J-Head' Casting.

When they left the Foundry, they left with 1.88" Intakes.

For the '340 Application', the heads were then sent to the Machining Division
and had the Intakes opened up for 2.02" Valves.

The Ports {Intake and Exhaust} and {Combustion Chambers} were all
identical for the {1971 and 1972} #3418915 'J-Heads'.

The