It reminds me of my engine, but way nicer.
I'm using a 4.185" bore and 4.125" stroke with RHS LS7 heads, Fast intake, wet sump and smaller cam, 244 259 @ .050. makes about 600/570 on a chassis dyno while being run up to 6800rpm. With the gearing and torque available it doesn't seem to make a difference when you shift as long as its above 6000rpm.
the way your engine builds power should be great for autocrossing. Always impressed with what comes out of the shop!
Matt