and just another 2cents- the gear vendors guys have a point- headers, heads, intake manifolds, carbs- they are all about making the engine work harder. Splitting gears is about getting more out of what you have- for my next project- I'm going to take a stock 75 camper special, leave the 360 stock (except for changing timing gears, and maybe rebuilding it to a 390), and try a gear vendor. Friend had one and his MPG was pretty good. They are pricey but no more than if you add up the cost of a manifold, carb, new linkages, headers, gaskets, & all the "while I've got it opened up" things- like tweaking porting, better power steering pump, water pump, yadayadayaday. fact is, trucks are barbies for men (or GI Joe's for me)- we spend more on the accessories than the ride.