recommend a jet size Holley 1920 slant six

Update

So I threw a 58 in there and WOW it really likes it. Now it can actually spin tires on dirt, which was impossible before. It's still got a weird bog on acceleration when it's cold but besides that the car is running a lot better. Now I just have to figure out what's with the bog and what that 2 inch flexable pipe is coming up to the air box, and I think I will be dialed. I suspect my issue might lay in a fuel hose somewhere with a crack in it, because the fuel filter refuses to fill completely.