29GMC

I got my first project truck and am pretty excited to start working on it. This truck was my wife’s grandfathers truck. It was on the road last about 25 years ago but to my knowledge he started it up every now and then. Gas tank is drained with no rust. I have a few questions can anyone identify the model? We apparently have a title somewhere but the estate is not finalized and they are not sure where it is. Second, I know it’s a hot debate so here it goes… add a lead additive or not, or marvels mystery oil, or any other additive? I plan on running non ethanol gas.