Hey all i figured i would share this piece of information that i wish i knew years ago. I've been messing with aftermarket TBI systems for a few years now. My first was the MSD Atomic EFI TBI system when it first came out on my built '87 trans am. And on my '79 Z28 I've had the Holley Sniper TBI and Atomic EFI. Now that the systems are in the $1,000 range more and more people are using them. Me personally i was never able to get it to run 100% on both engines. Messing with all settings i still had lean spots where the motor would fall flat or not respond correctly off idle. That is consistent across both motors on my built 87' and 79' camaro which has a stock motor and with both EFI systems. After doing some research i figured out the problem. Dual Plane Intake Manifolds. I recently switched to a single plane on my '79 and the difference is amazing, no more lean stumbles and extremely smooth throughout the whole band. I've seen many others report the same results. Engine Masters on youtube even ran into this problem with their Intake Shootout on the Dyno. They couldn't get the dual plane to run right with FAST EFI. They switched to a single plane and no issues. From what I've read the issue stems from the MAP sensor not being able to get a correct read because of the intake divider on the dual planes and/or how the dual plane is designed isn't the best for TBI. So if you're running one of these systems it may be a good idea to switch manifolds if you're having issues.