Chevy El Camino in the workshop

I've always liked the Chevy El Camino/Ford Ranchero idea so it's nice to have this come in. It'll start but won't run for more than a few seconds so I've got a few checks to do. An initial look at the ignition/choke wiring doesn't bode well, there's a lot of non-standard wiring and I've yet to find where it all goes/comes from. The carburettor looks recent, fuel lines look ok and there is a fuel pressure gauge fitted so I should be able to get an idea what's going on with the fuel system quite easily. It's also got a relatively new distributor with electronic ignition so that shouldn't be causing a problem.