pretty much looking for some guidance on this and how you guys might think of a better way to do this, kinda new to doing internal engine mods and all so, but this is my plan, i have a 2000 5.3L ext cab 1500, its currently on 35s. but i want ot lower it down and put 33s on it and just keep the body lift, i want to build the motor a bit to have a fun fast street truck but also when i want to i can still hit the trails, for the engine i was thinking about getting my heads shaved some to increase compression ratio and then maybe some time down the line get a some what agressive street cam, pretty much as big as i can get but still DD it, and i want to put 4:10s in the diffs to help with the 33s, what im wondering is how much does cam and heads effect MPG, i would like to keep it around what i have now, and would it be worth re gearing my 10bolt rear end and putting a true trac in it or putting in a 14bolt with 4.10s already in it with posi that i already have, just have to buy 2 new rims and have diff lugs front and back : \ if u guys have better suggestions to up my HP and or a better gear ratio then feel free to say so, thanks guys