93 mustang tuning problem

I have a 93 mustang with a 347 stroker and a paxton novie 2000. yes it has all the goodies and enough fuel and it is an efi setup.. My problem is that i have a shop tuning my car with a sct chip. At 5600rpm the car is putting out 511hp at the rear wheels on the chasis dyno, great right well everytime we hit 5650rpm the car starts to cut back like a rev limiter kicking in but i have the chip pulled on the msd box and the rev is set at 8000rpm on the sct chip so there should be no rev limit intact at 5650rpm. now we called sct and they said that they have heard of the 93 computer not havin enough memory for this much horsepower and that i need to change to a 94 computer because there was more memory in it and i should be able to reach my 6700rpm goal. has anyone heard of this or is there someone out there with a charger on a stroker pushing the same amount of horse with a chip setup... Any help would be great...
Thanks Ron

I have 50# injectors and a msd 6al box with a blaster coil and a factory 93 computer... I know lots of people can bring there car up to 6500rpm, i mean i could stop at 5600rpm but i know the car has lots more plus i have plenty of fuel and plenty of spark. im way confused and it seems like everyone else i talk to is also...