David Vizard did a lot af flow testing on 1.94/1.5; 1.94/1.6; 2.02/1.6 combinations with minimal port clean-up. Taking a 1.94 intake up to 2.02 with attendant port contouring netted marginal flow gains up to .500" valve lift. What he did recommend was opening up the 1.5 exhaust to 1.6. The gains here were significantly greater and worth the effort. And there is enough cast iron (usually) around the worn 1.5 seats to grind a 1.6 seat. Or if you decide to install hard seats, go with the 1.6 seats. I also like to put a polish on the valve stems - you can do this in your drill press using 600 wet-or-dry soaked in light motor oil especially when running "bronze" guide liners. BTW, Compe***ion Products in Oshcosh, WI sells a 1.9/1.6 completion kit which includes the Z-28 valve springs, stainless valves, seals, retainers, and locks at a very reasonable price. Look 'em up. If you have to pay a machine shop to do this work, you're farther ahead to pay a little more for a new set of Darts or World Products heads. Sell your 462s to a restorer who just has to have the "correct" heads on his 327!
The Jalopy Journal
