what is the benifit of installing them. i have an 08 street glide with python true dules , se aircleaner and a v% h programmer. the cams are out of an o7 fatboy with 100 miles on them,this is fact ,
harley states they are mid range cams,good to 5800 rpms, what will taht do to my lower rpm crusing

 

It won't hurt the engine or cruising at all.

 

I have Andrews 37's in my Dyna and the spec's on these are very similar (lift/timing etc) to the 204's although the Andrews has more aggressive lift ramps I believe. These are a pretty mild cam and there is no difference that I can detect in starting, idle or bottom end. Mid range and top end are stronger and it is perfectly happy on any throttle settings and road or engine speeds.
All you really notice is that from about 3200 is gets more eager to accelerate when you ask it to and it revs out higher.

I think you'll be fine.

 

The 204s are a mild cam but they IMO take what you have stock and give you more of it. They have a nice flat torque curve. I am more than pleased with mine. They peak at about 4k but come on in the mid 2's and pull strong all the way to just shy of 6k

 

I ran 204s in a previous configuration of my '05 95" Deuce, worst heads H-D ever put out and made 94TQ/85HP with a .030" head gasket to tighten up squish and bump up compression a bit and Python 3 2:1. Yours will do better because the '06 and later heads flow so much better; you will be all over 100TQ and low 90sHP. The 204s peak about 4200rpm and by 4500rpm they are fading fast but it is a very underated cam, IMHO. The .030" head gasket is important; don't go with the stock head gasket.

 

I'm pleased with mine. I have them in a 2009 Road Glide. They made around 81hp and 99tq with a mediocre tune. I'm running stock head pipes with bassani slip ons.