p/u I.R.S.

I am building a 1940 chevy p/u . I am using a C-4 vet I.R.S.and an install kit from a company which I will not name due to the fact that they do a good job building kits for 1947 - 53 Chevy trucks, BUT I HAVE A 1940! It seems everything I try is 4" wider than my truck. So I am willing to give in to the fact that I will need to shrink or cut 4" out of my kit & the rear end. The only thing that I am not sure of is the sway bar. How do I shrink 4" out of a sway bar or is there some place that makes custom bars?