FWIW, KenneBell makes this:
http://www.kennebell.net/accessories...boostapump.htm
It's on mine.<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> The Kenne Bell BOOST-A-PUMP™ is fully adjustable from 1% to 50% with the mere turn of a dial, so pump output can be varied to match your engine's needs. </div></BLOCKQUOTE>