find a 3.38 ring n pinion to drop the RPM [should be avail at specialty rear gear places, but also @ Patricks], and yes - get the temp up - always use a 180 stat for a 283 - they like hot and slow - they'll take higher revs, but they were made for max torque at about 2000RPM and will get better mileage there - sounds like yer doin it right otherwise!!
Bill
