i had a 448 with 906's and a tr with 2-660's, flat tappet cam that went 6.16, but that was at about 2825#. i believe we had one of the best set of 906's anywhere. with all due respect, to run those numbers anywhere but at a killer track and with density alt. air below sea level in a 70gtx weighing 3200 {is that with or without driver?} IS VERY UNLIKELY. i believe you said you wanted an engine that would stay together........ i don't think it will happen,sorry. maybe 6.40 to 6.70