Before I put the new 258 in my YJ, I had a lot of blowby also. My solution was this:
get a 90 degree elbow that fits the valve cover rear grommet.
run a big diameter (that fits the 90 degree elbow) hose over to the driver's side fender/firewall area.
get a "T" and run it with the 2 outlets vertical, and the one outlet horizontal - like a sideways "T".
Connect the one outlet to the hose from the motor
connect the bottom outlet to a quart-size oil container that is empty
connect the top outlet to a quality breather.
Now, with this system, you will breathe in, and any oil pushed out of the motor will be collected in the quart oil jug. Just empty the jug when it gets full.
Just be sure the hose from the motor runs downhill to the oil jug/breather.
This system works great, and costs maybe $5-10 for the hose and the 2 fittings.
I ran my YJ up to 197,000-some-odd miles before the new motor.