What big wheel kit are you refering too an offset axle kit?
the offset axle kit is more geard towards 121" suspension to allow for
inner wheel and scissor clearence.. in this case the 8" wheels are only run on the outside of the the shaft. and smaller 5 / 6" wheels on the inside..
I went with mountaiine machine extensions that are machined for big wheels.. Tracks USA Stopped supplying extensions for big wheels due to some issues with over tight tracks and no adjustability..
Since you got a 136" suspension.. you can try and use an 8" wheel.
are you going to run 4 or 3 wheels??
I went with 8" wheels from Avid

Avid
http://www.avid-products.com/catalog/index.htm