I am working the numbers on a 408 right now and specifying that it be able to handle my 300 shot nitrous on it. They have engines running 400 shots right now, so we'll see. They are recommending a special Wiseco nitrous friendly forged piston in the build up. Sounds like their builder knows what they're talking about. Give Billy a call at TRT and discuss where you want to go and he'll help get you there.