We track tested our hoods, with customers across the country, and starting with just our IROC-Z Hood (COPO style) we drop IATs by 13* on average over stock.
If you move into one of our IROC-Z Hoods with Louvers, my IATs were about 13* less than stock and I was running a Whipplecharger...
https://irocmotorsports.com/product-...z-brand-hoods/