Comparison 340 / 289

I remember a guy with a 66 true Hi-Po that I saw beat a good running 396 Chevelle and a 68 383 Bird. Don't know what he had done to it other than Hookers and a 3310 Holley but it was wicked quick. I'm sure it wasn't stock as rummors said he had forged 11 1/2's and a cam that only sounded a little more than stock. I'd guess he was turning 7500 rpm.
But the 340?
That is a different thing. I remember seeing a stock 70 Duster 340 but had headers, beat a stock 440 6 pak Road Runner. They ran late in the day at the track and the Duster won by about 1 car. I don't remember the times or speeds. I had a 56 Chevy then with 327. I wouldn't pull on the track with them because I'd already had my butt handed to me by the Duster (it wasn't even close). I went thru 7 engines with that 56 and after the Duster, I decided I wanted a Dodge/Plymouth.