I replaced my pwr steering pump on my '67 .. the orig was leaking badly .. the new one whines but I siphoned some of the trans fluid out and added Lucas pwr steering leak and noise reducer and it is more quiet now .. you might try that .. it can't hurt .. It is not too annoying now and I don't like noise that should'nt be there .. as far as a different source check with John Draxler at
Thunderbird Ranch .. let me know .. Gemman