Mopar Rich and I worked on an EFI tune today for a Barton 528. This is a pump gas street engine in a B body with an overdrive auto trans. Barton put a 283/293 flat tappet cam in the engine for some reason. Needless to say, it wouldn't idle at all with a standard tune. Rich was able to figure out a tune that allowed the engine to idle but it would die as soon as it went into gear. The tune session ended early when the starter bit the dust. So based on that experience I'd say be careful with big cams in pump gas engines, even if they are big engines. You might spend more time tuning the car than driving it!