If you use the following method you simply modify your existing Opti housing

Drill out the 3 drain holes with a 0.187" drill bit, get some plastic t-fittings, a y-fitting and tubing. Hook it all up with the GM 12556174 harness to your vacuum source.

BTW, this was the first time I’ve looked at the "Corvette Fever" mag, but I think it’s pretty cool. Lots of tech tips, even though they don’t necessarily involve an LT1. Oh, lots of pictures of sweet Covettes too J