Oil pressure problem?

I finished my 318 with 360 head build a couple months ago, and the only thing I've been some what worried about is how much my oil pressure drops when it warms up.
When I first start it in the morning the pressure is around 60 psi, but after sitting in traffic a little while it drops to about 10 psi sometimes even 8 psi, but as soon as I give her gas to go it jumps back up to 20-30 psi, or higher if I floor it.
I'm running 10w30 in her right now with a quart of the lucas oil that is reasonably thicker.
am I running the right weight oil or should I go thicker? or am I just worrying myself over nothing?
I replaced the oil pump with a hd unit when I did the rebuild.
The only other thing I thought of was maybe I tightened the hose to my pressure gauge to much and its messing up my numbers, is that possible?
Thanks for any help -Kory