You could buy books and attempt to do it yourself. The 80e is a very simple transmission compared to others I've messed with. You could go ahead and install it and then if something is wrong pay for a full rebuild. Bad thing is that once you go 80e you're committed to it. If something is wrong with the tran you'll be down during the repairs after being down while converting over to the 80e. Be forewarned 80e parts are bigger and pricey compared to the puny 60e stuff.

www.crateenginedepot.com has a flexplate, bolts and spacer all for about $50 for the 80e to LS engine swap.