X bl was always sold and advertised as the 340 X block so pick it apart all you want you'll have to take it up with the factory. Yes glidden's pro stocker was destroked still based on the 340 W-2 platform. I mentioned in an earlier post then I removed it that hot rod magazine had a great article article on their 10 fastest cars I believe it was called slicks and tricks where they put on slicks played with tune-ups and headers no internal modifications were allowed the 68 barracuda 4 speed made the top 10 no 440 or 383 A bodies made the list. And certainly no 360 cars no not even the little red express King of the smog motors