340 TA Heads....
the 3418915 head was used on 1970 340, 1970 340 six, 1971 340 and 1971 360. stock on a six it was the same size intake port as a four barrel, but with the pushrod passage moved over, the intake ports could be ground wider for about 10% more flow. back in the day the upgrade of intake was the ld340, then the portosonic, then the victor