[MJN]

If you are using a hydraulic lifter cam that will limit your rpm as stated above to around 6000 - 6500. I regularly spin my 331 to 6000rpm, but 6500 rpm is right at the limit of the hydaulic roller lifters. If you are running a solid lifter cam the next question is forged steel crank or cast crank ? and are you going to use a main stud girdle. With a good crank and the bottom end of the (stock) block beefed up you should be safe for 7000rpm. The problem with camming a motor to make good power at 7000rpm is that it will be a bear to drive around town due to the cam timing required. If you want a streetable motor (cam) 6000rpm seems like a good redline. A cam with 0.05" timing around 220 degrees intake 225 degrees exhaust with 112 degree lobe centers will make great power to 6500rpm in your 331 and still be driveable with a reasonable idle. You have a lot of cam choices in this range.