Highest flowing sbm heads?

W2’s make for a great head for a stock block stroker motor. With a little porting they can make north of 600 pretty easily. The one thing I recommend with any of the offset rocker heads is a solid roller cam with the offset lifter. It really helps with intake geometry. If you can afford it Jesel makes rockers for them and it would make for reliable power. I have harland sharps on mine and its like glass. It breaks adjusters occasionally and is generally a pain in the but. The harland sharps are 900 and the Jesels are 1600 so thats an easy yes for me.