valve spring retainers

Please educate me.
I'm trying to get the parts together for a stock 1970 head rebuild with Hughes 1110 springs.
What's the stock 318 valve spring retainer O.D." I see there's 1.5", 1.55, 10 degree, 7 degree??
I got the question into Hughes on using stock retainers with their springs, but wanted to ask
the question here.