I just got a datsun passed down to me, I need help keeping it run. It was already a previously restored Datsun for pure track racing purposes, it's *supposedly* had a new engine put into it and is extremely fast, so I want to make this a DIY project car. The dash has been completely redone up, witih all these switches on the dash with no labels.. theres like 20 ? And a few cut wires in the engine bay, and its been converted to a push start ignition.

So I proceed to start the car, realizing I dont have a key, but then it hits me, its a push start ignition.. so I push "start", no response.. I then think about the power supply, I look around, and in the trunk, there is a switch, i turn it.. power is on, faintly.. I push start it then, all the lights dim, and i hear little clicking... engine fails to turn, but almost does??? i play around with all the switches (feels like cockpit of an airplanene literally), i then push start, nothing.. I Replace the battery with a spare one, I push start, and it finally turns and the car is running.. after like 5-10 minutes of running, I turn it off, I then proceed to start it again, and Nothing.. it doesnt wanna start, the lights dimm while attempting to turn the engine but it doesnt..

I dont know what the problem is, the car previously hasnt been started for a few years.. The rear driveshaft had *supposedly* broke, so it was removed.. but that shouldn't be a problem, as I didnt put the car in any gear or attempt to.. I am thinking its the alternator, I dont know whether the alternator itself is broken, or if it's wired all funny... I dont know where to start, if somebody can help me diagnose the alternator, and help me make certain its wired up properly that would be great.

Where do I start to find the issue, and fix it?

If you need any more information on the model, let me know.