Andrews 57H or Woods 555 work well in the 103 and perform similarly. This opinion is based on real world experience.

 

2015 Road King

Thunderheader 2 - 1
SE 254E Cam kit
SE Super Tuner
SE Heavy Breather

Before/Base

77.06 HP
97.09 TOR


After/Final

89.09 HP
108.62 TOR

 

first you need to find a reputable supplier, then select the grind for you. Many quality suppliers out there. Look for a low RPM torque grind. The breaking point is max lift for your stock valve springs. I use Woods 555 cams in my '13 FLHTK Limited 103. Not sure they are the best but I made a decision and I like what I have.