You had mentioned 4.56 with 35s being a touch lower than stock with stock. Are you meaning a little less power or are you taking it literal like the 4.56 is a lower gear ratio than 3.55 and so you getting slightly more power than stock? From the gear charts i have looked at 4.56 puts us close to stock with 35s however it says when using an automatic trans add 100-300 rpm which would put us in the higher than stock category. From what i have read most v8's run around the 2600 rpm range stock at 65mph, the charts read it at a little over 2800 for 4.56 taking in acount the extra 100-300rpm for the auto slippage could be up to 3100 rpm which would put it in the range of more power/towing end? Does this sound on track with what you are saying?

 

You end up running higher RPM for the same speed, as compared to stock, with the 4.56/35 combo. (which is what you actually want with the Air Gap.)

Are we nice and confused yet?

 

this is going to be hard to explain.. Imah gonna try though..

more power doesn't equate to more speed or RPM by my way of trying to explain this..

if I'm running 3.55:1's, w/ 31's, @ 2kRPM, and in third w/o o/d engaged, it will take a small hill to kick me down to second gear.. the same truck running with 4.56's: the engine has to work less- and the tranny has to work less too.. that same small hill wouldn't load the engine enough to kick down the tranny.. or draw any more vacuum (which indicates the engine struggling to keep up)..

understanding where I'm coming from there may help explain:

the charts will spell out the absolute science/math of the matter- and they can't be argued with.. but they can't possibly know about your engine, and how much torque it's providing, and how readily available that torque is..

I hope you're tracking this, or you all gonna think I'm crazy...

in relation to most of our engines- they are capable of producing enough power to do whatever we want.. BUT.. they are dogs throughout the entire RPM range.. better in some places, worse in others.. if you can bump them a little, and allow the engine to get a head start on the overall gearing, they do just fine.. (unless your racing).. as long as you can find a 'sweet spot' where the relationship between your drivetrain and your power plant doesn't over-load one or the other, you have torque available when you want it..

in short- an un-loaded engine is coiled and ready to spring, where a loaded engine will take time, distance, fuel, patience, and stress on parts and pieces to respond..

gearing the truck to what you're doing is the cheat sheet. You can achieve a speed vs. load ratio that is suitable for economy (all things considered), performance (uhem), and sustainability by just changing the gearing.. a vacuum gauge is indispensable for proving this..

if you're still tracking, or if I'm doing a decent job of explaining- in direct response to your question: The 4.56's, on 35"x12.5's, powered by 5.9L Magnum V8 and with an intake manifold that raises the torque curve- I have a lot less load on the engine overall.. as a daily driver, and as a hauler.. being low on load allows better, and more efficient in terms of fuel consumption and time, response from the truck.. THAT, was better than stock..

it's not that I'm producing more power to the terra by itself, it's that I'm putting at least equal power to the terra- but I have a ton of power instantly available if I need it, and because I've lessened the load on the engine with the gears..

an engine running easily at any given RPM will be more efficient than one struggling (loaded) at the same RPM.. the argument is, how many more RPM's until they equal out? My guesstimation: a helluva lot more than the documented difference than 3.55 to 4.56, or 3.92 to 4.56, or either to 4.88.. keeping the load off the truck is the key.. if you're maintaining a low load with 3.55:1, hell- stay there.. but I don't think that's possible with heavier tires and decreased leverage...

does that make sense?