I just rebuilt the head on John's 261. Here's what I used:

Exhaust: www.ebay.com/itm/156769335932

Intake: www.ebay.com/itm/122009255781

The exhaust seals ride up and down with the valve stem. The intake seals clamp onto the guide. Don't use the O rings- - - -that's too much sealing. Put short pieces of electrical insulating shrink tubing over the valve stem keeper grooves to avoid seal damage as they're installed. The 1.94" intake valves are OK, but they really can't benefit breathing much because of the geometry of the intake ports and manifold runners. They were only used on Powerglide equipped spray oiler 235s from 1950 to 53. A better idea, (and less expensive) is to use 1.6" stainless steel small block V8 exhaust valves and a camshaft such as the Melling CCS-1 which increases the exhaust duration. That provides better cylinder scavenging on the exhaust stroke without creating a rough idle.

Edit: Did the machine shop recess the intake valves the same distance that they milled the head? If the margin of the valve is exposed to the flame front that travels across the surface of the head as the spark plug fires, the valves will burn very quickly. I was given an 848 head recently because of intake valve burning- - - -the valves were not recessed after the head was milled, and the intakes lasted less than 10K miles before burning.

Jerry

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