Best plugs for street 340? Thanks for all the input!

No assumptions involved. I ran E3s in my 08 Jeep Wrangler. It got crappier mileage and threw misfire codes left and right. Also caused the engine to occasionally shake the entire Jeep like torque converter shudder. Put the Champions back in and it was perfect. It's not just with computer controlled stuff either. They plain SUCK.

The iridium stuff is different. That's not even in the same category as multiple electrode stuff. These old engines don't need all that fancy stuff. Be dumb with your money if you want too. The farthest I'd go if I wanted an "upgrade" would be to something in NGK, but there's no NEED for that. All a spark plug can do is spark. And that's the truth.