340 with edelbrock heads overheating

if you dont want to centerline the cam, install it dot to dot and use it that way. checking lifter height at tdc is not precise enough to set a cam. your intake lifter being higher than the exhaust only means your cam is advanced, but you dont know how much. your cam requires 104 degrees intake centerline, which would be 4 degrees advanced ( 108 lobe separation minus 104 intake centerline). i would think your cam grinder is right in saying to leave it alone if you set the gears dot to dot. the cam you got is not for racing use, where you would want that last ounce of hp. for a street application, you wouldnt FEEL the difference if you centerlined it.
your cam is probably already ground for 4 degrees of advance already.