You seem to know that of which you speak, which is refreshing as in most forums people have opinions but not experience.
Was thinking of doing either and all aluminum 3.25 stroke 347 or the same with an iron block. The theory behing the iron block is that it may be allowed certain historic race classes.
Currently though I do about 10-12 trackdays per year, so primarily the car is for that. But you never know.
Comming froma lotus lightness is next to godlyness, so my inclinationm is aluminum block, but then if iron is better/easier to keep in lash and has poettial historic raceability it tips in that direction.
the people at Keith Craft reckon that with roller rockers and not too extreme a cam ist should go 2000 miles plus between adjustments.
If its going to be 500 miles then maybe I will just do the aluminum 363.
Would really appreciate your thoughts.