according to some tech bulletin from chevy someone here posted not so long ago. The corvettes came with out manifold heat and wasn't actually recommended except for extreme cold weather. I haven't had heat on mine for 3 years and it has never ran better. Even when it is below freezing. (not much below, as I don't live in Minnesota or wherever it gets really cold) So I wouldn't say it was essential. Unless of course you live where it is very cold and actually drive your truck in the winter weather.
Last edited by brokenhead; 06/27/2013 8:17 PM.
