technique to sealing a oil pan on a 360?

I have to agree with the bodywork part too. Lay the pan on a flat surface and make it mate. If the leak is at the back of the engine it might be the rear main seal or the rear main bearing cap leaking. I use very small amounts of RTV . When a gasket doesn't want to lay in place I'll tie small pieces of sewing thread through a few bolt holes. Once the bolts are started the tread is cut and pulled out. This helps a lot when the gasket was wadded up in a box.