will stock rockers work with larger springs?

La valve spring installed height is about 1.69 in for heads in good shape. So maybe .11 inch difference. How did you get to 1.80? Valve? Retainer? The OD of the spring just gets less than a eighth of an inch higher. Do you have everything? Did you mock it up? Nothing weak about factory rocker arms. As I said before, the factory ground clearance into the rocker arms on 340's.