[gtohurstjudge]

I bought some no.48 cylinder heads 10 years ago and stuck them on a shelf and decided to sell them, but I had never looked at the date codes until
now, but the date codes end in a "1" which I assume to indicate 1971, but 48's
were 1969 model year only.......so what have I got? I've inspected them carefully....
the raised casting numbers have not been tampered with. They are high performance heads with big valves and screw in rocker studs. Did Pontiac do
another run of these heads in 1971 for service replacement purposes?

[Baron Von Zeppelin]

Its possible
Usually SR heads have different markings from production heads.
An X here or an O there (raised cast digits) just as examples..

We would need pictures to cross reference.

Would be the first pair of 48 SR I've ever heard about - I think ....
Roundports are about the only SR's that come to mind at the moment