I have these in my motor and i run a .670 roller .280 at 50 int/exh, with 76 cc rpm's and steel shim gaskets.
Mike

69 Dart GTS 440 mopar .590 cam, Edelbrock heads, 3200#
best et 6.45, 106.78, 10.14, 132.88 mph, 1.47 60ft
best 60ft 1.36