ive been studying these plans that i came across. there supposed to be based on a sierra.anybody used them.are they any good.http:locost7.info/files/chassis/Chassis_Sierra.pdf

good drawing just needs to be on autocad

Not sure about whether it'll fit a Sierra but the front two TR rails (is it TR5/6??) are the wrong way round!
They should go from the top of FU1/2 down to the front 'H' rails not vice versa.

James