swirl port heads

Yes I have on a fairly recent 340 rebuild. "J" heads I had were trashed and I started looking around and it turns out that INDY recons these and sells them for a reasonable price with 2.10 and 1.65 stainless valves complete. I think I paid about $550 plus shipping and new head bolts. Car runs mid 13's with Holley carb, Edelbrock air gap intake, TTI headers and 3.55 rear end. From what I was able to find out these flow better then "X" and "J" heads. I don't remember the casting number series for these but believe they were used on mid-70s police cars. Might be info on www.allpar.com
PS: I believe we figured my final compression was about 10:1