I'm building a slant six (225) for my '64 D100. The head has been milled .100" and I have .465" 280 deg cam with 1.7 intake/ 1.44 exhaust valves. The block has not been decked yet, but I will assume that it needs it. Assuming the block is decked the "normal" amount, do you guys think I'll have to notch the pistons for valve clearance?

If I do have to notch them, how do I konw how much to notch? I know how to measure valve to piston clearance with a lump of clay and lettinght valve make an impression in it and measuring, but that only works if the vlave does not hit the piston. How do I figure how deep to go with the cuts?

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Stephan Nelle

You loosen the valve lash until you get the needed clearance, measure the lash, add a little more for "insurance" and machine the notches.
Be sure there is enough thickness in the head of the piston before cutting metal.
DD