I've got a '72 suzuki xr400 I've removed the engine from to install into an old Yamaha Blaster quad frame. The problem is the exhaust won't fit, so I'm wondering if I can cut the flex pipe off the header, put a bend in it to bring it out the side instead of straight forward, extend it out longer than it would've been stock, and possibly add another bend before matching it up with the old expansion chamber. Would this completely change the optimal rpms it was tuned for in a bad way? Should I try to construct my own expansion chamber with the formulas I've found for figuring basic dimensions? I'm not sure I could find an aftermarket to match up like I'd want and quite frankly I probably can't afford it if I do. Any help would be appreciated! Thanks in advance.