Helped do an EFI conversion on the dyno the other day. Engine is a nice little 331 inch SB Ford that is going into a Bronco. AFR heads, 9.2 compression, small hyd roller cam, etc. Started with a 600 cfm Holley carb and made a little over 400 hp then switched to the MSD Atomic. The engine ended up losing a few hp with the EFI but it sure is smooth. Starts right up, idles smooth, etc.
The Atomic is super easy to install. Just need a wideband in the exhaust and a coolant sensor in the hot water. The computer needs power and ground and it needs a fuel pump that can put out 40 psi. It only took us a few minutes to have it installed and running on the dyno but obviously in a car it would be a full day project if you had to mount the fuel pump and weld a bung in the exhaust.