Top end upgrade, stock motor
are the "first limit" to how high the stock
motor can safely be revved.
With minor intake improvements and a not-bad
exhaust, my engine doesn't seem to be "falling
down" the back side of the torque curve yet at
the 6KRPM upshift. Long term reliability concern
is what keeps me from pushing the shiftpoints
further upward.
So I'm wondering, would a simple springs upgrade
make it safe to hit 6500RPM on a daily
basis? Springs & rockers? What minimum upgrade componentry
would it take for a "close enough to bulletproof"
top end?
I assume that you're still running the stock cam (since the springs have not been changed). If so, why do you feel the need to shift at 6,500? Have you had the car on a dyno to see where power peaks, and where the optimum shift point is? Every stock car that I've had on the dyno has peaked around 5,300 - 5,500. Beyond 6,000 the power drops off drastically.

