ok, heres the deal. I am going to put a 400 swingarm/shock on my 250x frame, already got 400 a-arms and shocks up front. anyways I measured and the swing arm mounting bolts are a shy 9 3/8 and the 250 its a strong 9 1/4 so there is less than 1/8 an inch I get to remove from the mounting tabs, maybe Ill make new tabs to go alongside the stokc ones and weld them to the frame so they will be even beefier mounts than before even though ive removed some material. now the rear section of the swingarm is 6 1/4 on the 400 and 5 1/2 on the 300(same as 250 right) but the sprocket is mounted much farther away from the swingarm than on the 400 so they are about equal lengths from center of swing to chain. also I measured on a running 400 and a running 300 and they both are 1/2 inch from chain to pivit mount on frame. and I can weld the tabs for the dogbone link easily. and about the resorvoir on the 400 shock, its in the way of a frame rail on the 250 frame, but I can turn the shock so thats in the rear and it wil clear it until I go to install the air intact duct. right in the way. I was thinking of a couple PVC elbows with some flex hose inbetween them but that will be way more restrictive than the straight shot it has now. so I am wondering what shock I should use that has a forked end that can bolt to the 400 link at the bottom but doesnt have that external resorvior or if it does its a remote resorvoir I can mount somewhere else. or a shock with an eye on both ends like the stock 300 but a longer length because if I go straight to the swing with the stock shock it seems like it will sit loew and not have the gretaest travel either.