So would I benifit in running a shorter shock and keeping the stock mounts
You can fix a 12" shock under there with careful planning of the lower & upper shock mounts. You might get away with using the stock upper mounts but you might need to build a upper shock mount like this
http://www.yotatech.com/f115/blisten-5150-mounting-question-223636/I doubt you can fit a 14" shock down there without major angle (like I have). I don't suggest it, the shocks are not efficient that way.
From 4Crawler.com (
http://www.4crawler.com/4x4/4R_suspension-III.shtml#ShockAngle)
"So what does velocity have to do with anything? Well, a shock absorber, assuming a common hydraulic design as is commonly used in vehicles today, is a device that generates a damping force that is proportional to it's speed or velocity. Ignoring friction effects (like the seals inside the shock) and spring effects (such as from internal gas pressure) and variable damping rates (as from progressive shocks), if you compress a shock twice as fast, it generates twice the damping force. Likewise, compress (or extend) it half as fast and it generates half the force. OK, so where does this take us?
With the shock at an angle, it moves slower, relative to the suspension's up-down motion, and the more it is angled over, the slower it moves. Thus, if the shock compresses or extends slower, it is creating less damping force for a given suspension speed. So this is a dynamic factor affecting shock absorber performance.
Going back to the first part of this discussion, you need to combine the static and dynamic effects of the shock's mounting angle to estimate the overall effectivenss. Since both effects are independent, their combined effect can be calculated by multiplying the factors, which in effect squares the values in the above table
sin(90)^2 = 1.00
sin(75)^2 = 0.93
sin(60)^2 = 0.75
sin(45)^2 = 0.50
So we can see from the above table, that the shock effectiveness falls off much faster than could be accounted for strictly by the static effects of the mounting angle. And if you look at going from say 45 degrees (0.50) to 60 degrees (0.75) the shocks would feel 50% stiffer at 60 degrees vs. at 45 degrees (0.75/0.50 = 1.50). And going from 90 degrees to 45 degrees, the shocks would feel 1/2 as stiff. The above is a long-winded way of saying that as the angle of the shock decreases, it pushes less hard less efficiently in the vertical direction."
