The wiring is relatively simple for a race car.
Keep in mind I have only wired GM's and Toyotas with internally regulated alternators,and you are going to need some help from the Isuzu wiring Gurus concerning the ignition hookup and the charging system.
Positive battery cable to starter,negative battery cable to chassis(ground strap from chassis to engine recommended),hot wire going through your starter button to "S" connector on starter,hot wire going through toggle switch to ignition.
Now some folks use their ignition toggle switch for the electric fuel pump also,I prefer to have seperate switches for the 2.
I also HIGHLY recommend a rollover cut-off switch between the fuel toggle switch and the fuel pump.
An electric fan(with seperate switch) and oversized radiator is also a very good idea.
As to where you should hook up your igniton wire someone else will have to chime in,on my Toyotas I am able to run power to the positive side of my coil and it's good.
Same thing with your charging system,one of the experts here will have to advise you so as not to go frying things and blowing up batterys.
Hadn't gotten the chance to look at the rules for the Thunderdogs before I went to the Stateline jamboree on Saturday,but after asking a few folks about the track and the class I was told to go home and look at the rules,then ask about setup.
I did.....
I'd think you would be better off concentrating on surviving rather than winning.
13.1 ELIGIBLE MODELS - Any Car, Van, SUV or Pick Up approved. Oversized vehicles are not approved. 13.1.1 Thunder Dogs are CARS THAT WE RACE NOT RACECARS.
13.1.2 Any 4, 6 or 8 cylinder engine approved. Any modifications approved.