At the moment been in the middle of revising the plan set. There's a few engineering and note errors in this plan set its amazing. Some of it might have been conversion errors from converting metric to standard. For example the main frame section, is stated to be made from 1 1/2"x1 1/2"x 0.065" tubing. That is far too thin to be safe for my snowmobile engine. I am bumping up to either 13ga or 11ga tubing.
Also abandoning the a-arm setup and going for heim joints instead which will give more flexibility and adjustment over the fixed geometry. Another thing I have to change is, the axles are not setup for plunge. Even assuming equal length A-arms, there is still a margin of error that the axles would need to plunge. This is where using a CV axle or U-joint with a slip joint in it is key. In fact most builds do switch to CV axles because of this reason.
So while I am waiting for the temps to become reasonable, I am revising the design, cleaning errors, and modifying to work with my engine and gearbox combination.