Best bet would be a T34 with a .48 exhaust housing to make that sort of power.

When you say "low comp" how low ? - anything below 7.8:1 and I presume you intend increasing the power further at a later date ?

I would say that especially since you've just had the engine rebuilt, a proper breather is not essential, but it would still be a worthwhile mod.

HTH

Edd