What size valve cover spacer and where to get one?
Any other head mod needed or machining?
A waste of money with 6800 rpm max?

 

basic valve cover spacer (I guess.....I went the tall valve cover route)

yes the heads need to be clearanced at the back or the rockers can rub

probubly.....it depends on how much spring pressure and such you are using. I did them because:

a) I have Comp Rs that need 0.002" preload
b) I have high spring pressure
c) I wanted to be able to go solid lifter in the near future