<VV> Bronze alloy for valve guides ?

[D. Monasterio]

    I remember have seen 1 or 2 years ago some postings about the adequate bronze alloy for valve guides. Went to the archives without success so, this is time to ask the experts.
    I am in the process of repairing a worn hole in a head, enlarging it to allow the instalation of a custom oversize (maybe up to 0.030) valve guide but, if my 3 remaining neurones are working fine, I think there is the right bronze alloy (phosphorus, manganese, etc. ? ) for this purpose and there is a no no alloy.
    Do somebody remember which is the right alloy ? BTW, are cast pistons suitable for top milling... say 0.060" ?

    Thanks a lot for any response

    Daniel Monasterio
    Guadalajara, Mexico