6200! you wuss! my 451" rb has been 7500 by accident.. lol stock rod stock crank. Used to shift it at 7k. Ran that short block for 9 years never tore it down.. Just cams and heads.. lol
Honestly, I don't think the 906 heads will let it! IIRC the cam is good to 6800rpm. I built the bottom end bulletproof and was told by the machinist it is balanced to 9000rpm.