Finally received the last piece to my F1000 trail sled that I raced on asphalt. This is a stock F1000 head that Speedwerx machined to cut the domes out of it. They are then replaced with billet domes. This can be done to many of Arctic Cat's laydown engines. You can run any type of compression ratio Speedwerx offers with interchangeable billet domes. It is much more cost effective then a complete billet head. Also is very stealth for all those "stock" sleds you find out on the lake. Nobody will know what you have under the hood with this set-up. I'm sure Jim from Dynotech Research will find this interesting. He has never been a fan of the large "bathtub" style billet heads. They seem to show a greater difference in water temps between the two sides. He likes the stock head where he feels water velocity is faster and does a better job of cooling than the larger and taller billet heads.