rough idle at startup

[shavedchevy]

here's the deal..... I've got a stock 1986 350 with a lot of miles on it, when I start it up in the morning (after sitting for more than 5 hours) the thing just doesn't want to stay running, so I give it a couple quick revs and it fixes that problem.

Then when I leave it for about 5 or so minutes it gradually builds its idle up to about 1750RPM ( which is just roaring with my mufflers) so I rev it up once and it brings tthe idle back down around the 750 RPM mark about where it should be. Then all is fine

My question is, was thi normal with this style of engine or is there some kind of quick fix I could do to prevent this. It's really not all that bad when it does it when it's cold out but when its warm out I do't want it to run like this.