I ran a 650 double pumper on a .040 over 360 in my 4x4 in 80`s,it had 12-1 jahns pistons,strip dominator manifold,13/4 headers,2.02 int valves.First thing I thought was maybe a little over carbed on 318.But reading thru replys they are good with fix tips.Mine was 75 white sweptline express with keystones and 12/33 15 tires.Twisted yokes on transfer case pulling wrecker and mobile home out of mud with both burried.I did not lack for power.....lol