You gotta do the 144. I bought a 136 E.G. complete topend for my '83 yz125 at the beginning of this year and it screams. The bigger bore and porting made a big difference. It came with the new rebuild kit & gaskets, used intake manifold, reed cage with boyessan reeds, and all bolts for $375 shipped. I wanted to build an aluminum frame yz144 recently but the blownup bike that I found on CL sold pretty quick. The 144 is worth the money if you prefer to ride a 2stroke.