Got to give a shout out to ESP for outstanding work on their mods to 1/5 scale rc engines. I picked up a ESP race mod big bore kit from DDM when they went on sale over the holidays and WOW. The machining on these is top notch. The work is so good its difficult to tell its been done after market! I'll be doing a how to vid on the install once I have all the parts for my engine, and I'll post a link here once its up. Here's few photos of the cylinder head.