I had an engine that didn't seal up right away..an engine builder friend had me go on the highway and run it up in 2nd to about 3500 then let off and come down to almost an idle, then up to about 4500, and back down, up to 5500, and down..........a couple miles and she was all sealed up. No guarantees, but it won't cost ya much to try. I don't know about an electric pump, but I've been told to remove the belt from mine when driving on the street, because the seals go away too fast.
I don't really think electric pumps really do much compared to a belt driven pump. Do a search around on the internet but I don't think many guys are running the electric pumps if they want any kind of performance advantage. I run my belt driven pump on the street, not every day, but I am not afraid to put miles on it. It's a GZ Motorsports pump and the oil mist that it suck in actually helps keep it lubricated and it pulls killer vacuum.
Electric vacuum pumps are as good as belt driven provided they are a pump designed for racing. Star Machine probably makes the best electric and belt driven pumps available. The little OEM type pumps or ones designed for power brakes etc. aren't worth using IMO. http://www.starvacuumpumps.com/viewPart.php?id=STR.04.06.000
I first tried the cheap route by stealing the AIR electric pump out of my Corvette. It wouldn't even move the needle on a vacuum gauge. Sooo, I bought a GZ Motorsports pump kit. It's holding up well on the street so far. Here is a link to his website, with my installation shown as the first picture: