I don't think they will fit Ben. I can't really tell you why...but they always sell them separately. If you have a 2-bolt block, yes they most definitely worth the money. Supposedly, it gives the block more bottom end strength than a 4-bolt main block. If you can picture it in your mind, it makes a big torque box out of the bottom end by connecting all the main caps. The result is that you couldn't budge one main cap without deflecting the other 4. Very stout.
Most main girdles come clearanced for stroker rods. Mine did. I ordered one from Ford Performance Solutions....it's .400" 4340 steel....and unlike others, it includes the loop around the
oil pump. Some that I have seen just cut this out altogether, or not even include the front cap. It also comes with ARP fasteners....I'd go with studs. From an engineering standpoint, studs are stronger, because they have no head....i.e. no place for stress concentrations to gather. All of the stress goes into tension on the stud itself.
You can get a good one ready to bolt on (including fasteners) for under $200.