Remember .......if a company sells a fan without saying it is a true pusher...it's a puller. And it will not work well as a pusher if you have to turn the blades around and rewire it to run as a pusher.
Again.......Spal makes a true pusher or a true puller...they won't sell a puller and tell you to turn the blades.
Spal is also factory on the new Ferraris..........there web site is..........Spal-USA.com
When measuring for space for a fan, always give yourself at least 4 inches extra from where it attaches to the radiator to the front of the motor. Always look for the HP after the fan number. Spal mkes lots of fans but the HP versions are meant for the hot rod motors.
Using fans from some stock applications may work ok, but the downside is those fans are meant to cool the HP of that motor. You need to have a fan that will cool HP.
I can tell you that a twin 11in fan setup from Spal will need 24 inches of finned area of the radiator to fit it.
And finally...........I don't work for Spal.........I work for Evans cooling............but we do talk to people all day and tell them the same thing about Spal fans.