George HI
did rebuild an Cleveland from stock to "modern" update under German cost aspects 
..and followed George P`s detail description. Du to same as I read issue on German cost to manufacturer I did go Trick flow 195 with Hydro roller and 10:5 static. Engine runs Impressively. strong.
1) if you need I have 2 original 4V Heads open chamber coming from a turbo jet 1976. Heads are in running condition.
2) René a fellow from France did modify stock heads in France , he has all details on modifying the heads and make them more "aggressive" as adding lift , still hydro flat cam so my understanding. So you want to reach out to him , and there where some issues in positioning the rockers adequately. Think he had a machine shop on Elsass for a decent cost.(??)
3) I did go a different route, Trick flow heads, Hydro roller, New intake (needed modification as used the Edelbrock performer..mods on the openings per CD camera and blue print, milling the top angle of the intake to make it "flat" as OTC has an decent angle.....all this saves def 20..40 kg weight..
and engine is running very strong..too strong so to say..awesome
Regards from Stuttgart area
Matthias