Wolverine350R

You could get the V6 and the 4.8 in a 5-speed. There is at least one T56 swap on youtube. (Video Link)

Mine, stock.

Check behind your fuel tank (hopefully its there), I am not sure what year they moved them. On my 99 it was on top and there is no way to get to it without removing the bed (but that isn't to hard). First photo here is where it was on my 99: http://www.justanswer.com/chevy/16x63-evap-canister-vent-solenoid-valve-2004-silverado.html The mount just to the left of the highlighted 2 is the forward most bed mount. This links photo is with it off the back of the tank: http://engine-codes.com/qa/6146/p0449-gmc-where-is-evap-located-so-i-can-replace-it I hope that helps, good luck with it. Here is a link with the GM TSB with photos, but I think there may actually be a newer one also: http://www.justanswer.com/chevy/1bo37-code-po446-evap-emission-control-system.html