I am running the XE 227/233 camshaft at the moment. I have Lloyd Elliott ported heads with Combination Motorsports 612 springs. Here is a link to one of my more recent dyno runs. See how the power peaks about 5800-5900 and fall straight off. I pulled the car to 6400-6500, but as you can see the power had fallen way off by then. I know that the XE grinds tend to fall off quickly at 6000 or so, so maybe I am just expecting too much out of the cam. So, for you dyno graph gurus, does this look like valve float or is the car just done making power at 5900 or so?
Also on a side note I am considering changing over to a CC306 camshaft. Does anyone know right off hand if the Combo 612's will support the 306? From what I have read the lobes aren't as harsh on the 306 and I figured I might be ok with the 612 springs. Thanks in advance.
Hopefully I can get this to link up right.

http://etrackmasters.com/dyno/joshKr.gif

 

I would think something is wrong. I'm no expert, but that just doesn't look right.

 

doesnt seem to far off to me.

do a search for dyno graphs and compare them.

 

Looks like it to me. Whatever it is, I wouldn't spin it over 5800 until you get it sorted out.

 

Looks like many XE grind dyno graphs, including mine, and yes I also think its valve float.

 

I was thinking that it was valve float, I just wanted a few more opinions on the graph. This is just one of my more recent dyno runs with this setup. My best run was 356/350, but all of the graphs look similar to this one at the top end. I have had my doubts about the CM 612 springs handling the XE grinds above 6000 or so. Lloyd did my heads and set up the srings so I know that they are correct. I have heard that the 612's don't really like to hold anything .570 lift or greater above 6000 rpm. I am not sure how true this is across the board, but for my application they don't seem to be doing the job. I think I am going to swap over to the Crane dual spring kit and see how well it pulls up top then. I just had it retuned and it is cleaner up top now, but the graph still shows problems.