what would you guys do? LS vs 454?

[324matt]

Well, my 350 in my 1985 k20 is leaking oil out of the rear main seal, and now the front of the oil pan by the harmonic balancer. It has 120k on the odo, so im sure the days are numbered. Check the gas, filler up with oil. I had a good line on a 6.0L 4l80e and tcase from my local honey hole for $300, but I had to take it out. Today I spent 2hrs un clipping the wire harness, removing the front end to get to the motor, only to find out it is locked up. Its a 6.0L core. The trans oil is burnt bad in the 4l80e also. I really want to do a LS 6.0L swap just because of the learning experience and my truck would be bad to the bone after it was complete. I have a line on a 5.3L with a 4l60e that is not locked up, but I'd rebuild it anyways. But then I also refresh craigslist every hour at work to see what I can make a few $$ on, and I come across deals like these.

http://stlouis.craigslist.org/pts/4874448220.html

http://stlouis.craigslist.org/pts/4847412547.html

http://stlouis.craigslist.org/pts/4828225911.html

what would you do if you were me?