I can tell you that what George is saying is the exact thing I am going through right now. We have an older Rupert 950 that we had on a 468. It had 165 jets in it, I put it on my 383 that is a lot milder motor that the 468 and have had to go up to 173 jets, went quicker and faster than with the 165s, and I am going to go up even more the next time out. I am using an electric pump also. The one thing that I will have to watch with an electric pump is emptying the bowls faster that the needles will let fuel in with the bigger jets because I can't raise pressure with rpm like a mechanical pump, even though that is probably the better way to go.
Curtis