can anyone tell me where to get measurements for the mounting holes for an extra 12 w/121" in an older early 90's indy chassis,i found the extra10 diagram from jb shocks website,but no one seems to have the 12 info.i have heard its a pain but i stick to trails only and i need the softest ride possible.plus its a great deal

After doing the same thing last year I came to the conclusion I would have been better off selling the old sled and buying a more current model. Its a lot of work for what you end up with.

thank you,thats what i keep hearing but the deal was almost too good not to consider it,i will get a 10 or a newer sled.

Here are the problems with doing this mod. My sled is a 1990 indy 500, 579 xlt triple with psi pipes. Rear suspension is 1996 extra 12. Once this is done you will have approx. 300 lbs of ski pressure across the spindles, this is measured with a scale and a piece of 2" x 2" square tubing. This is to much ski pressure and makes the sled almost impossible to turn at slow speeds. To correct this you will need to modify the front end. I am usuing the 1990 trailing arms and spindles. All other front end parts are from a 1997 indy 400 xcr with extra 10 in the front. This works quite well. If you are still want to do this this mod I can send you the measeurment to relocate the tunnel mounting holes. Seeing as I have don these mods I would recommend buying a sled that has extra 10 or 12 suspension. It is cheaper in the long run. Been there done that.

that is good info thank you.but i talked to a couple of people that had done the extra10 swap and they said it was easy and night and day difference, so thats what im diong.thanks