:agree
Unless you're going for originality or date-correct parts, stick with the 670's. Some folks claim the 670 to be one of the best heads Pontiac made. They have 2.11 intake and 1.77 exhaust valves and a 72cc chamber, vs. 1.92 intake/1.66 exhaust on the 092 and 093 GTO heads. Main difference I know of between the 092 and 093 is the combustion chamber size...the 092 has a 68cc combustion chamber and the 093 has a 70cc chamber. Plus the 670's are kind of rare, only having been offered for the 1967 model year. I think the GTO actually ran a 093 head, but the valve sizes are the same as the 092. I've got a set of 670's on the work bench, just spent a wad on new Ferrea valves, hardened seats, Comp Cams springs, locks, retainers, valve guides, roller lifters, ARP studs, etc etc. They're going on top of the 461 stroker I'm building. But I'm always looking for another set.... I'm running a set of 092's somebody before me put on my '67 Lemans, they are correct for a '66 389, although I believe they are 2-barrel heads. Interested in trading for the 670's by any chance?
KB