If you aren't using an onboard starter, you can also vent the crankcase by puting a plugs with a hose barb in the starter hole and run it to a catch can. In my cases, I disassembled an old starter and used the head piece since it already the right size. I went to the local hardware store for a hose barb that was threaded about the same diameter as the opening where the starter shaft fit, then simply threaded it in. I siliconed the plug in place, connected the proper size hose with a clamp with the other end to a catch can and you're done. Made on big difference for me to lower crankcase pressure that was causing oil leaks on my 1030cc drag race motor.