Yep single slams are the best bang for the buck. Stock sleeves are alot stronger than b-series. Unfortunately, the heads don't flow as well and they are minus one cam. I've seen some builds of sohc pushing 30+psi on stock sleeves. Only thing I would do besides the bottom end is definately go with an aftermarket valvetrain, or at least titanium retainers. No one likes to drop valves.