The 337 is a 4150 flange, and is a very low profile. I wrote down the height difference in my notes, i would have to dig them up to see the exact difference(iirc it was close to 2 inches lower at the carb flange than my M1). I ran it for a short time and wasn't impressed, but after reading some of these responses about it in this thread, I'm wondering why I lost ET compared to my M1 ? maybe it's my combo ? my engine didnt seem to pull as hard thru upper rpm with the 337 compared to the M1. I lost a few mph with the 337.
https://scontent-iad3-1.xx.fbcdn.net/hph...110097384_o.jpg