Installing 5/16" top nailed hardwood

JDittman

I recently bought a foreclosed 1939 colonial with 5/16" top nailed red oak throughout w/ the exception of one room which has linoleum. The hardwoods are in great shape but the linoleum in the single room was horrible so I ripped it out. There is 3/4" diagonal plank subflooring beneath it. I plan to install more 5/16" red oak (will refinish everything at the same time). I understand that it will not match perfectly. I am in the process of identifying the species, cut, etc.

My questions are:

1. Is any sort of underlayment required before I top nail the 5/16" red oak?
2. What type of nailer/nails should I be using? I have a 16ga trim nailer and an 18ga brad/staple nailer.

Any advice would be appreciated.