Rear main seal repair

[Beatcoaster]

All,

My garage is not setup for the repair of a rear main seal leak I have identified on my "new to me" 307/350 69 c10. The previous owner said the engine was rebuilt at some point by the original owner but didn't know the timeframe. Due to the above, I am questioning whether to drop $500 for a rear main repair at the local shop, do it myself(god forbid it's a one piece and/or something goes wrong and I just spent $100 in parts/oil and my truck sits in the driveway), or just save for a new engine(my uncle has a 383 roller he will sell me for $3000)...Regardless I am needing to swap the 2bbl carb/intake/headers/exhaust anyway(it's all original) so I am truly debating the costs that I am facing in the near future...Any ideas or thoughts from the wisdom bank that is this forum?