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[HD Street Performance]

Think again
They have 175# on the seat and they need that the valves are big and heavy. I'd say based on my experience you may loft the valves if you go down that road. Correcting the geometry has the valve starting to lift with more acceleration and the lighter spring sounds dicey to me especially with that cam. Want to test and find out?
I have lofted valves when going too light, not pretty or quiet

[Hekterr]

Deweysheads,

You're probably right..My experience with 140 lb springs was in a FXR evo motor with 1.9 valves..The se 103+ heads have a much heavier 2.08 valve in them..More weight and mass does take more spring pressure to control..
 The cam card says stock springs.. so I thought the SE springs were overkill...
  The lofting problem..Is that the result of heavy valve/light spring, or agressivive ramps on the cam lobe..(thinking of roller lifter follower spring kits in high rpm chevy oval track motors...Might be a "new" invention for HD motors.

 First I'll have to get both bikes dynoed to measure their output..
Then I'll try the geometry stuff...
  If the power output on both bikes is similar(within 3-5hp)and the noise level doesn't come down on the SE heads, I'll switch back to a set of nicely done stock heads with the 7mm beehives...
 I was wondering if side to side clearance of the rocker arm generates much extra noise...(they seemed pretty tight, around.012) We used to quiet down shovel motors by adding shim washers to the rockers to cut down on side play...
  Didn't mean to hijack this thread..Just wanted a quieter engine..

                   Thanks ,Dave

       

[HD Street Performance]

Stock OEM 7mm = 88g
2.08 = 112g
OEM beehive spring 130# nominal seat pressure
SE double spring= 175# nominal seat pressure
valve weight relationship= 78.5%
Spring pressure= 74.3%
4% is pretty close, just saying
The factory is not too far from the mark here Dave