VALVE CLEARANCE

Hello John,
i have installed a spitfire profile cam with beehive valve springs from Jim Scmidt.
i suppose i should contact Jim direct but  he will expect some figures from me.So thanks John , i will look for around 40 thou minimum.. If less than 40 thou then do you know any shop that sells a  thicker head gasket in the U.K.?
Road not race.
I will look out for Dunstall tuning notes but i thought it mainly covered cam timing.
I will try an art shop for the modelling clay.

thank you for all your replies.
a thicker head gasket could be preferable to piston pocket machining but i may have no choice if the valves contact the piston. and the piston looks high to me.
i am using this second hand cam follower conversion to triumph R cam followers , spitfire cam, which has been a little harder than i thought as the locating holes of the blocks were drilled too low and i had to start again.
Jim Schmidts U Tube videos are excellent.
valve clearances and pushrod length still to do and its only a road bike 500cc.So is it worth it?
i will try Michael Balls suggestion first [ without cam chain first , then with cam chain connected ] as the method will tell me if i m in the park or not.
Thanks Guys., its the suggestions i needed.

Well the inlet valves made contact with the pistons which i think was due to using larger inlet valves from a  99 cylinder head on a 88 barrel and pistons. so  clay next.
The Gandini pistons i am using protrude about 0.8 mm above the top of the spigot. I think that is too high.  Any opinions?
With the cylinder head located on the barrel spigot , without the head gasket, the gap is around 0.6 mm and the cylinder head gasket is 1 mm thick. Not much room for error?
Any opinions?
Off course, using barrels and heads from different years and cc will throw up issues but other than time consuming , its all quite interesting. A bit like doing metalwork at school all those years ago.

hi micheal.not hard to find a problem with piston clearance as the engine would not turn past either inlet valve. i should have checked the valve pocket size before assembly but its  a piston machining issue now..
thanks for photos David. my piston protrudes as far as yours so i must have the same high compression. What was the engines performance like.Was it peaky? pinked? I feel that i don t need high compression nowadays with all the risk of holing a piston. But i also remember that the dommies sometimes felt down on power around the 60 to 70mph mark. I m using a non downport, 1960, 99 cylinder head. single carb.