52mm TB

Is a 52mm throttle body a good pickup for a 305? Is it effective with the stock plenum, or do you need to bore the inlets?

The stock 48mm throttlebody fwill flow more air than a well built 350 can use, so no, a 305 with a 58mm TB would not be a good thing. The TPI system needs higher velocity air to pack the cylinders, due to the length of the entire runner system. If you put in a large TB you'll be effictively slowing down the air and will actually hurt performance.