You have the 5.3, so bore it to 5.7 so much more piston selection and a few more inches, I'd go for around 11:1 as far as compression. A set of 243/799's worked and cleaned up a little bit. A cam in the 23x/23x .6xx/.6xx range, an LS6 or FAST manifold, appropriate fuel system and bolt ons. Put it front of a built 65e with somewhere around 4000 stall torque converter. And if that don't work