what setup should i go with
 

My E-Maxx is stock sept for single speed conversion and steel idler. Wondering what motor and esc to go with for 14 cells and speeds of 35-40. Also what kind of runtimes will I be looking at with reccomended setup? Thanks in advance.

7xl or 8xl should do the trick. You could get the MM if you plan on going no higher than 14 cells and I'd use the 8XL to keep the current down. If you may go with more cells or 5s lipo, I'd get a Quark 125B. If you want a better quality motor, you could go with the Neu 1512 2.5d. It will stay cooler and still have tons of power.

Say I go with 8xl, MM, and Maxxamps 2s2p 6000mah packs...what run times would I get and will it run cool.

Runtimes depend on many factors: weight, gearing, terrain, drive style, etc, etc. The best thing to do is go through this thread and find a setup most similar to yours to get a rough idea. But, at a guess, I'd say around 30 minutes.