Patman,
15-20 second idle sounds OK to me. I like to let the engine warm up to 1/3 normal heat reading before I rev to over 2,000 rpm's.
If any of you guys have oil presuure gages, what range do you see from cold to warm to hot and with what viscosity of oil?
In my '86 Burb, 10W30 synth, I see 60+ psi when cold, then drops back to 35-45 psi when warm, then settles out to about 25-30 psi when hot. This is at about 2,500 rpm. I should also mention I have an oil pump that is not considered a racing pump, but is a higher volume pump than stock. Some might call it a street pump.