Need help determining if this 700r4 will work for my set up

[conoco]

My truck
1972/k2500/th350/np205

There is a guy in my home town that is selling a 700r4 for $600. I am going to go look at it this week because those are few and far between where I am at. It is currently matted to a 1984 suburban and also to a np208.

My question is will this 700r4 mate to my np205? I understand the splines might be different. I just figured even if I had to buy some parts/adapters to make it work it would still be well under the gearvendors unit.

I know there are also some variables that I might need to work around. My understanding is the 6 inch tail th350 the 700r4 will swap right over and the short tail will need 2 or 3 inches cut off the drive line. I will measure mine when I get home but I am pretty sure its the short tail. I am just wondering if someone could let me know everything I would need to make this work. I don't want to waste this guys time or mine. I am all for buying the parts to make it work but I guess it all the depends on the modifications that would need to be done. If it gets to crazy ill just keep the th350 and get the gear vendors. Thanks everyone.