Bone head move, or hint of a problem? Overheated in driveway on fast idle.

[spamtank]

I pulled the car out in the driveway today to wash off the underside, after getting caught in some precipitation last weekend on the "last drive of the year."  We had snow the day before, and I didn't think they put any salt down, but I noticed some indication that I was wrong during the drive.

Needless to say, I wanted to wash off any traces of that before I put her up on jackstands for the winter.  So I pulled her out into the drive way, and figured I'd let her idle while I hosed off her belly.  Probably took about 20 minute to a half hour till I fished up.  When I hopped in, I realized it was on fast idle, and the temp gauge was just crossed the upper normal line.  I kicked it down off of fast idle, and backed in in the garage, and shut her off.

At that point I had antifreeze venting out of the overflow tube and makeshift catch bottle. 

I don't really have temperature problems when I take a normal drive around town and on the highway.  I'm just concerned that this may be indicative of problem that will rear it's ugly head when I least expect it.

Any thoughts or comments, or is this just a bone head move by the short circuit between the steering wheel and the brake peddle (yours truly).

In case it matters: 1970 SE, 383 2V  AT with a 26" radiator, and AC.

[MEK-Dangerfield]

I think you are fine. Just be glad you had a 26" radiator.

[femtnmax]

 
The AC condenser reduced airflow thru the radiator, and discharge into the overflow container after shut down is exactly what those containers are for.  With the correct radiator cap the radiator will draw the overflow  liquid back in as the system cools down.
With the cooling system COLD, when you check the radiator level the liquid should be at the sealing surface for the radiator cap, not down anywhere close to the hollow tubes/fins of the radiator.

[Chryco Psycho]

what are you using for a fan ?
 it still should not overheat ,but I agree that pushing fluid into the overflow is normal on a hot shut down