Ok, I thought upper factory hose was 1.50", its 1,25", so I think I will get both because they're cheap. I will have to drill out the 1/8" npt to 3/8" npt since my sender is manual, and the right size one I found for $20 does not have a ground screw, kind of a big deal.

I'm not exactly sure where you're talking about. Do you mean the temp sender in the upper hose going into the radiator? If so, the factory hose is 1-1/4" and the radiator inlet is 1-1/2", so depending on where you're adapting it up will change which size you need. The sender coupler I used was an 1-1/2", though I may have accidentally listed it wrong in the post.