47 degrees initial time? help!!!

Good job. 34 total is a pretty safe number for an iron headed SB. It may take more as you get things sorted out. You might want to figure out if it will take 24 or 26 initial to give you some wiggle room. Say the engine likes 36 or 38 total... you need to either bust back into the distributor or twist in a little more initial. :)

Contrary to a lot that is written, I like to do the inside limit points when welding them up. Sometimes help to slow the advance a bit with faster advancing springs like the MRG units.
This is an interesting option that also depends on your choice or assortment of springs and rotor indexing. Limiting the slot inside or outside can keep your rotor closer to the pole in the cap under advance and is a good way to help solve this issue if the rotor is getting farther from the contact than you like. If you have an old cap to cut open or drill holes in and inspect rotor alignment this will tell you which method is better for your application.