Yes, there are still a good amount of these kicking around and they do make respectable power. They really were rockstars when 23 degree technology sbc stuff stalled. Fast forward now though, and Guys like Darrin Morgan and Chad Speier are doing things with 23 degree heads that were unthinkable 20 years ago, (although you have to run a large x huge cam). The high-end stuff now is the 9/10/13 degree stuff from shops like MBE and RFD. Not uncommon at all for SBC-based guys to be bolting on heads that will flow 400+ on the intake... Flow numbers are ONLY 1 piece of the puzzle for heads, but let the idea of 1 intake cfm for every cubic inch sink in. Guys like Al and Shiloh know full well that end of the spectrum. That's why their stuff runs crazy fast