slant 6
 

just started rebuilding cylinder head on my 1973 225.I started to install the valves,I installed the valve ,seal,retainer without the spring on it then raised valve the .400 that the camshaft lift is and the retainer seal and top of guide hit at .380 binding the setup every thing is just the way it came from factory,should have more clearance with valve seats cut and valve resurfaced and the seals are the stock umbrellers type seals, is this common ?and every part is factory org.any thoughs guys? thanks I know you can cut the top of valve guides down for more room but this is starting to cost a lot more money .