Hi Will,
I'd also be interested to hear Tom's reasoning on this modification. I was all set to do it and asked the same question over on the Chevy Talk board http://www.chevytalk.org/fusionbb/s...1/hl/oil+pump+modification/fromsearch/1/ and it was agreed that plugging vent was unnecessary. Sealing the pump at the inlet is crucial however. Do let us know what Tom has to say!