Allan Futral definately knows his stuff. He made 492 rwhp and 411 rwtq form a stock block/crank LS1 with ported LS6 heads, stock computer(link below). Only internal mods where rods and pistons. It also has a custom sheetmetal intake along with the usual LS1 mods. This car is raced and see's occaisional street duty....driven on occaision by Allans wife. So its not an all out track car. It will be soon though. It still has a few things to be done to it to get it over the 500 rwhp mark such as electric water pump, vacum pump, etc.

He also just put out a motor with a resleeved 397 all bore alum block, still hyd cam setup, stock crank. It made 510 rwhp and 490 rwtq. Daily driven. These are not extreme build ups either. Nothing special about them except the combo of cams, heads, and tuning hes using works well.

His prices are very reasonable too.
Another reason why I think the LS1 based motors are the best small block ever made.

Futral makes 492 rwhp from 346