One thing I just thought of is the spacer and crush plate you will need for the airplane. You can get it through Just but they only have the 3" I think. I wanted the least amount of extension possible. I tried to make it work without but it just wouldn't. If the rad was back a bit more it would though. I got a 1" spacer and that gave me lots of room. I also kept the cowl fairly tight to the spinner but it fits really crappy. Like 1/8 clear on one side and 1/2" or so on the other. It's sure not an RV fit, I sure wish it fit better but it was not worth all the work and added weight to redo the cowling.
Good luck
