The problem with the stock block is once you get around 8k rpm, and higher. It wasn't designed to rev that high, and thats when people have problems. VTEC motors live in high rpms, and that is where the LS/B20 block fails.
__________________
2015 Ford Mustang GT Fastback - Ingot Silver - 6M - Performance Package - Gibson Catback, JLT CAI, FR 47lb injectors, BAMA E85 tune, Eibach Sportline, BMR wheel hop kit, UPR oil separator, Steeda shifter bushing/bracket
Team B.O.B.® - Ballaz on a Budget