Seen that before. you sure the crank is shot you may be able to have it trued and welded, check it out before you buy a new one. The other guys have good ideas, go port job maybe cool head, or have your head shved down, have the carbs worked on and defintely go with some pipes.
I went with LRD pipes because they will give you more mid to high range, but if your looking to just ride trails the toomey t6 is a bad ass pipe.
95 shee
bored .60 over
lighted flywheel
rewound stator
dune port
milled head