need crate motor advice

[May70]

I need to purchase a motor for my c20 project. I would like a simple 350 turn key crate engine with efi. Its going to be a driver and I will tow a 7k car trailer occasionally. Im also leaning towards getting a different transmission because the original 4spd manual granny trans isnt the smoothest cruiser. I want something smoother than that for cruising. I want to go 65 mph without the trans wound up.

Not a big fan of a seasoned/reman block but ive never owned one. I see Chevy Performance 350 turn key is about $6k without the efi throttle body and the zz6 is like $8500. Pretty expensive but there seems to be only a few thousand difference between a brand new engine vs one with used block/heads(?). Seems like a few thousand bucks is well spent for a new engine.

Anyone got some advice for me on this? THX