Got my cam.

The STL2420-I6-10 sort of favors your 355s. I think is was referred to me by Hughes as a 70% Street, 30% Race. The 2016-I6-10 has a better operation for higher compression engines, have you milled the head or the block? Your 500cfm will work good on 2420. Did you read the section on their (Hughes)site about choosing the correct cam? It has a lot of questions answered there.
Norm