I had the biggest, baddest 16" fan Permacool makes and later a 16" Flexalite fan on my Cobra and it was marginal. Just installed a Spal 16" straight blade fan and it made all the difference in the world. After this I would not buy anything else but a Spal. They may be noisy, but move air like no other. CFM ratings on all fans are bull**** because others were rated higher than Spal, but you can tell a lot of difference after installed. Bought mine from
www.streetrodcatalog.com for $125.00 and had it within a week. I drove cobra off and on most all day today and it never got over 195 degrees. Used to get up to 220-230 and once to 240. It was 94 degrees outside today.