[mlgreen]

I have an '84 (carb) so this may be of limited use to you. Anyway, the initial startup rpm is probably normal. Mine has a "fast idle" and a slow one. The fast is designed, I believe, to get the car up to operating temp quicker, so that the car is more efficient. As far as the low-idling goes, 400 seems a bit low. You might be able to look on the underneath of the hood to see what the idle should be (it could be somewhere else in the engine compartment too). It varies depending upon whether you have an at or mt. I would guess that your rpm should be about 6-700. I'm not sure how you would adjust your's, my carb has an idle adjust screw so it doesn't take much imagination. ANyway, my idle is supposed to be correct, but it still feels as though it might stall sometimes, but never does.
Also, my temp gauge often goes above 1/2, sometimes up to 2/3 or maybe 3/4. I was really concerned initially. My guess is that they didn't have an efficient enough cooling system or that that range was normal for that era of cars. Just make sure it doesn't get too crazy and don't worry about it. You could need a thermostat, but mine's new and it still does that.
Good luck