A vacuum pump is only going to help if you have the rings to use it. The 30+ hp comes from using low tension rings and the vacuum seals the ring to the piston land. I had one engine built with low tension rings. I used an electric pump for this. On the Cobra I've got medium tension rings and also run negative pressure in the crankcase. With low tension rings if you don't run negative pressure you'll use
oil like crazy. I've got a couple of electric pumps that I'm not using if anyone is interested, both are GM models.