Just got a 84 YZ490 motor. Thought i might put into YZ-H 81 frame.Will need to swap barrel to fit single down-tube. I think piston\barrel\pipe from IT\YZ465 and 82YZ490 will go on.Will 84 piston interchange with 82 YZ and IT490,was told pre 84 is different?? 490 heads,are they the same??Also will the off-set airbox (IT\YZ 83 on) fit somehow , so can use barrels with angled intake(83 on).Any ideas or sugestions would be cool. If my thinking is correct, any parts out there.