Comp grinds their cams 4 degrees advanced so you can get the proper timing while still installing the gear straight up. You can also buy a timing set with multiple keyways so you can set the cam at -4, 0, or 4 degrees. Timing chains are cheap, I bought a Comp Magnum chain for only $29. Also, there is going to be more strain on your timing chain with the bigger cam so it is probably a good idea to just get a new chain anyways.