Universal sending unit help

[McKenna]

Hey guys I have a 1970 C10 I'm slowly working away at putting a 6.0 LS into. I'm just getting to the fueling part now and I am looking for some help on my sending unit.

I have a friend who has offered to make me a tank for next to nothing all tigged out of aluminum so I have found dimensions online for an under the bed style I just can't figure out what I'm going to do for a sender as I suspect using a factory GM unit would be quite difficult.

I guess what I'm asking is what would you guys use? Is there an aftermarket bolt in sender I could give him a template for that uses the 0-90 ohm (I think that's the right ohms for our truck) I'm Just thinking a bolt in unit would be less head ache for him to fabricate

As well would you guys run an external pump or try to find a sender and use an internal one? Pros and cons?

Sorry for all of the questions I just have a dead line as his boss is only on vacation for so long haha and I have no experience with GM fuel tanks this being my first GM truck or EFi conversion