[Power Surge]

Do you want to really want to meet EPA standards, or do you want to meet legal state inspection/smog standards? There's a BIGGGG difference.

You'll NEVER meet current EPA standards with any carb. Just won't happen. Even the best full boogie adjustable race carb (fully adjustable metering blocks) doesn't have the ability to control fueling for what it would take to meet EPA specs. Then you also have no EGR, no canister purge with a carbon box for fumes, etc, etc. How do you control NOx? How do you control the 200 rpm increment between 3400-3600 at 60% throttle where specs go out the window? You can't.

You'd need a modern fuel injection system (i.e OEM spec, not aftermarket), and you'd need to have it properly tuned, on a 5 gas setup, to meet EPA specs. Oh, and that's even if the basic engine design even let's you get close enough to EPA spec.

On the other hand, you could easily build a emmisions friendly car that meets state smog tests. Just having the most basic crude, nothing on it, carbed Cobra PROPERLY dyno tuned, should give you excellent emmisions. My brother's 331 stroked small block, with 6-71 blower and two Demon 650 blower carbs, gets 18 mpg crusing. Why? Cause I spent over 2 weeks tuning the car RIGHT. That doesn't mean it would ever pass a state smog test with that kind of setup of course (the part throttle and WOT would be WAY too rich), but you get the point.

However, back on topic.... I've seen many old muscle cars converted to propane that have zero emissions, and actually make more hp because of the octane rating. Not the most convenient fuel to run, but then again, what is other than gasoline right now?