Mechanical Oil Press Gauge ?

[Big Kev-O]

I have searched the threads and I can find any information on what the pressure range is on a mechanical oil gauge. I think my oil pressure may be a bit low at idle. When it idles cold it is in the dead center. Once the engine warms up it is just under the second line. Cruising warm it looks good. My previous engine was a worn out 81 350 and the needle was always in the center. My current motor is a crate 350 I picked up from a "friend" who said it had about 40K miles. I downsized the cam when I got it and rebuilt the crappy chinese MSD streetfire HEI. When I installed the SF HEI it seemed to have alot more wiggle room than the GM HEI in the old 81 engine. Could the SF HEI be my culprit? Is this range safe?
Thanks.