Where does the extra 55Hp come from between an LQ9 and LS2??

From what I understand, the differences that matter HP wise are basically the intake, cam, and compression.

LQ9 has a smaller cam, lower compression 317 heads that flow about the same as the 243's and the truck intake vs. the LS2 intake.

Is there anything else that would figure into the 55Hp difference?

 

put 243 heads on the LQ9, an ls6 intake and the ls6 cam in the lq9 you then have the same or slightly more power then the ls2......

lq9 and 243s are same cr, ls2 uses a ls6 cam and the ls6 intake flows more then the ls2

 

I thought the 243 heads had a smaller combustion chamber and a higher compression ratio, but flowed the same as the 317's. Would it really be worth getting a set of stock 243 heads?

 

they flowthe same but the 64.5 cc compared to the 72 cc is where it gains a full point of cr