I don't know if I've asked or read about this but some info in a response Mark Parker made about his valve clearances in his all alloy engine had me wondering.

If a cam manufacturer asks for .010" cold clearance for say a Triumph 650 750 performance cam, are they expecting or would they like to see this same .010" when the engine is hot? So many variables could change this dimension from heat expansion in a stock vs. modified engine that I can't see this spec not changing between engines. Would it be safe to assume that the cam manufacturer designed the cams ramps etc. around the .010" and the only way to insure this would be to come back and set the lash hot? Otherwise, whether one used iron vs. alloy barrels or steel vs. alloy pushrods would determine what lash one ended up with hot. I've never checked a Triumphs lash hot when using a performance cam so don't know. Thoughts? Mark R.