A just bought one and this was the best deal I could find. Reher Morrison and some others have a 3 vane Moroso complete kit for $799.00 and $119.00 for a regulator that goes on the pump instead of the valve cover, for a total of $918.00 plus shipping. The regulator on the pump allows cool air to come in at the pump keeping it cooler when you reach your desired vacuum. Autofab race cars has a 4 vane Moroso pump kit for $889.00 and if you want the regulator at the pump they will swap it out with the valve cover one that comes with the kit. total cost with shipping $949.00. The 4 vane pump by itself it $200.00 more than the 3 vane. I thought this was the best buy that I could find.
http://autofabcart.net/morosocompletevacuumpumpkit.aspx