Can I replace my 383 rear main seal with motor still in the car?

I will relate a story of my own. 318 poly fresh build started leaking bad after about 4k miles. Really dumped oil on the headers during acceleration. Thought it was the oil filter gasket. Nope, couldn't figure it out but oil was all over the headers and under the trans inspection cover. Thought it then had to be the rear main seal. Nope. Upon close inspection, the rear oil pan rubber seal had slipped out and was letting oil slosh straight out. Dropped the pan, reinstalled the rear seal with gasket adhesive and it has been 100% sealed since.