Originally Posted by tubbedz
I don't know if this helps, but on my, TH350 automatic, 671 blown SBC, I would experience "detroit Roll" at idle. After many hours of double checked timing, gaskets, etc... I tried increasing the idle feed restriction jet on my billet metering blocks. Guess what happened....the surge went away. The blower was sucking my Holley, idle feed restriction dry. So I increased the restriction jet to allow more fuel at idle. Correct me if I am wrong, but this is just my own personal experience. I am not saying this is a cure-all modification, but just an example of unique situation that I ran into and wanted to share my experience with my fellow Hot Rodders. There maybe other factors or issues that are unique to your situation.
Exactly what worked for me. Super simple fix. Don't turn'em but a twitch or you'll run too lean. I run the boat at an altitude of 5K and running 91 pump fuel so I'd rather be a little rich. A roll of about 500-700RPM is okay, any more and it gets out of hand. The cam-roll/idle-roll in my case is a necessity rather than a "cool thing". I'd rather err on the safe side (rich). The motor you see in my pix is in my V-Drive, 22' Schiada Day Cruiser. 468 ci BBC with AFR 305 Alum Heads and other goodies.