Yep, I do the PCV valve on passenger cover and a K&N open breather modded to fit the stand on the drivers side cover.

I've used cheap, chrome Mr. Gasket breathers in the past and they simply can't flow enough air at higher rpm. Years ago my dipstick would blow out of the tube because of crankcase pressure buildup with one after 4.56 gear install..

'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.