Whenever I try to shift at high rpms around 8000-8500 rpms i try and put it into the next gear (so far only tried 2-3rd and 3-4th shifting at high rpms) it grinds and doesnt find the next gear meaning that I put it into the next gear but it wont go. Is it most likely the synchros in my transmission? How much are the parts to rebuild my tranny to get it shifting smooth again and where can i find them? Thanks in advance!

James

By the way its a b16 tranny.