Take a pic of the casting shapes on the front of each cylinder head...it looks like someone just threw in any old spark plug to fill the holes!
Also post a pic of the spark plug seat area in each cylinder head...where the plugs screws in....
Is the distributor an standard points type or a HEI unit? Edit....dont bother...its a HEI unit from the pic of the carb....it could have been incorrectly wired when someone changed over from points to HEI....check the power wire for the distributor has full 12 volts when key is in run position....sometimes folk forget to replace the resistor wire in old points systems when changing to HEI
Thanks
