There's more to building an engine and making horsepower than just bolting on a head.
I call bullshit on all these 450 hp 340's, it ain't as easy as some say and it's been witnessed at the track.
Back around 1977-78 my 340 street car ran 11.82@3200 plus pounds. .30 over bore size, .585 solid lifter cam, j or x heads with 2.02 valves, port a sonic intake and a 850 Holley. I was a street racing young punk that didn’t have a daddy to help me learn. All we had were some books and magazines. Now all someone has to do is go on forabodiesonly and listen, read, and learn. We have laid out the blueprint. If you Dont think technology has come a long way since the 70’s you are a nut. You guys always use these horsepower charts so here’s my numbers. And this was keystone not some east coast super track.