New 350 HO GM crate engine, have a couple of questions?

[Jonce]

I'm new to this site and it's been really helpful so far.

Here's my current setup - 1971 GMC 2WD stepside, 350 CI (engine knocks), and 3 speed on the tree. I ordered a GM 350 HO Turn Key crate engine (Part #12499711) 330 HP/380 Ft Lbs Trq. This comes with a full serpentine setup. From what I have read, this should be a reverse flow water pump. Do I need to change out my current radiator with a newer style radiator? I just want to make sure that I get all the pieces before I start the swap.

I also had a question about the 350 HO Turn Key engine. It lists the flex plate as being a 14" flex plate but looking at the part number (#14088765), this is supposed to be a 12.75" flex plate. Does anyone know for sure what it comes with? Reason for asking, I need to buy a TH350 and torque converter and I wasn't sure if this would effect it.

Can anyone recommend a good street setup for transmissions? I have looked at the TCI Street Fighter at Jegs and Summit but haven't had any experience with that paticular tranny. I'm not looking to race every weekend but I want a reliable setup - please list some recommendations for my new engine.

Thanks guys!