You can inject just about anything from a Brigss and Stratton up. Many many ways to approach the problem
The new Holley HP/ Dominator/ etc stuff has versions that can be programmed with a handheld device and are "self learning," or you can piece stuff together using Ferd, or GM ECU Lots of dope.
Wander over to the "binder planet" where many guys have modified IHC engines using GM ECUs,
or Google up "Megasquirt"
http://www.diyautotune.com/?gclid=CNuY4Ku55rUCFe9aMgodrQYACA
