if you don't care to run wires allong all the engine bay, I you can go directly to radiator core support ground point... or even in fact directly to batt post.

However that is too much wire going through engine bay without need for that. You can try also a stud, or bolt with a nut from inside the cab somewhere at firewall on a clean of paint spot and also run up to there the engine ground strap.

You can weld the bolt to from inside the cab too, going through the firewall.

Another posible good spot and won't need anykind of job are the wiper motor studs!!! but thats MAYBE some far away from block to attach the engine ground strap, I mean if you take the idea to use the same spot for it. It is at least a little bit far away on B bodies. Maybe not too long distance on A bodies. You can also get a longer ground strap too to get it.

just some ideas comes into my mind right now.