i have a 5.0 roller motor , x300 cam and a set of 9.2:1 289 heads, tunnel ram 2x4's . not sure if this will suit me yet . looking for a set of the 10.5:1 heads. before it is over i may just go ahead and and bump it up to a 12:1 motor , will be running a 4 speed with 4:11 gears and tall tires. not looking for drive-ability or millage .