74 225 slant 6 options

SS is right...

get a new set of autolight 66 plugs REMOVE THE WASHERS!!! and gap to .035"... go to a 65 if you mill the head...

Slow down trigger.
Are you sure he has the drool tube head ?

pretty sure drools went away in 76 but being im on my GF's computer (mine died) i cant look up my chart... but thats a good point...

to OP, is there an aluminum tube around the plug? or is it just the cylinder head?