I am running a little low on funds, trying to build a powerful LS1 and a powerful 5.3, and was wondering if I put stock LS6 heads on my 5.3 would I tell any difference? I was going to have them ported however, I am spending it to install a cam with the heads. So would it be worth using the LS6 heads, cut 20 thousanths for compression, or to back with the 5.3 heads.