I use the Goodmark Cowl hoods they seem to fit the best and look the best. I have been using thier hoods for over 6 years and really like the fit. You have to do a little work to get them to fit perfect but for out of the box they are very nice. Here are some trucks with them on it.
http://www.feslerproductions.com/1967ChevyTruck.htm
http://www.feslerproductions.com/1968Chevytruckpur.htm
http://www.feslerproductions.com/1968HHChevyTruck.htm
http://www.feslerproductions.com/1967Feslerblazer.htm
http://www.feslerproductions.com/1969FeslerCamaro.htm
These are all Goodmark hoods hope this will help you out