Fast idle is slow to come on

[K10-Kansas]

Hi all! When I start my truck it idles at 600 for about 30 seconds and then the idle climes to 1300 over a duration of about 10 seconds. Then I tap the gas and put it in gear and go.

I'm pretty sure that a few years ago, I'd start it in the morning and it would go into fast idle immediately, and then after 30 seconds, I'd tap the gas, put it in drive and go.

The way that it is acting now, fast idle is pointless because the truck is warmed up by the time fast idle kicks on.

I have a 2nd Gen, 5.7 V8, Blueprint crate engine with 3,000 miles with a Holley 600 CFM 4 barrel with electric choke, and vacuum secondaries - 4160. Blueprint said this is similar to a stock 1986-87 GM setup.

I've looked at the fast idle cam, screws, etc and everything looks good. The idle speed is not the issue, just that it doesn't go into fast idle until 30 seconds after start. That's not normal right?