This is a aftermarket air bonnet for a 427 HI-RISE intake. I've had it for 20 plus years, not sure who made them. I never used it,but i have had it on a hi-rise engine for fit & show of fitment. I can send more picture using email. Sorry not good at this. I want $325 & yes it does have the finned top. I have 2 cars with 427 hi-rise engines this fits both cars. The center to center on the holes are 9 1/4".