Tabdoo,
you may want to check this article out. This person used a 63 IFS and removed a couple of inches from the cross member. Nice picture and fairly well documented.
We're thinking of going this route myself. we're going to change the rear end out to get the open drive line, so matching the track width won't be a problem and my oldest son is a welder,so fabrication isn't an issue.We
Only concern is keeping the tires inside the wheel well.
http://www.chevytrucks.org/tech/1963-1987%20IFS%20UPGRADE.htm
