If you read BPE's account of how the dyno was acting, it's very apparent that it wasn't the engine acting up on the dyno, but the dyno servo load control was bad. A friend just experienced the very same problem with his dyno.
I could all very well be true... but I would still want to see some Dyno sheets before buying these heads.
You would think that someone selling heads would have at least one running engine with them before marketing them...again not trying to be critical... but I would want something before spending the cash
