You will need a better idea of what your axle ratio. With out a tach you won't be able verify how close your "327?" ratio is. I've seen 3.30, 3.42, 3.55 ratios mentioned quite often. You will need to know what your tire size is by diameter. Then you can use an RPM calculator to determine RPM;

http://www.csgnetwork.com/multirpmcalc.html

I don't run a 235, so I'll leave it to others to say what RPM you should run at.

Larry

I don't own a vehicle that isn't old enough to drink.