Hi All I currently Have a Holley 670 on my 350. Just wondering what effect a 20 Degree increase in ambient air temperature will do to idle quality. I was out of town for business and when I got back avg temp had gone from 60-80 degrees. All of a sudden car Idles real rough. I made no other changes. was wondering if air temp could be the issue?

Thanks
Chris

I dont really have an answer for that but I was actually curious myself as the last week has been really hot and my car idles very unsteady and rough until the temp gets down to about 80 or less then it idles pretty awesome. I have noticed this before but always figured it was because my car isnt tuned good but I think big cammed motors probably respond more to this. I have a low quality cooling setup and water temps reach 200 on a hot day mostly 190.

On a cool night if I forget to turn on the fan and the water temp reaches 200 or more it doesnt change the idle but a hot day at 180 water temps its rough. Just though Id add some comment, Im curious about this.

No doubt the underhood temps on a hot day are much much higer since the radiator is throwing off a lot more heat. This heat would warm up the carb and intake to a higher degree.