"...Not sure which heads the 68 350-HO came with..."
#18
http://www.wallaceracing.com/enginesearch4.htm
This really has almost nothing to do with this thread. But, since I'm a drag racer, when I hear about a '68 350HO, I now automatically think of Adam Strang's '68 Bird Stocker. He tried a 350HO in it & ran some 10.80's, IIRC. Did I mention that this has almost nothing to do with this thread ?