Not a fair comparison, as the X head has a better short turn.
This one used an 11/32 stem 2.055 valve.
Basic full port and polish, no holes in port other than v/c bolt hole.

Lift----IN flow
.100---65.4
.200--128.1
.300--187.8
.400--234.3
.450--257.7
.500--272.9
.550--276.7
.600--272.1
.650--270.3
.700--270.3

68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads