Smokey,
I've heard they won't fit with any of the aftermarket cross members a few times but don't remember their being a definitive. I was running a M2 Car cross member in my 53 1/2 ton and it worked just fine, don't know how the aftermarket one's differ. Did TCI say it would work? I'd start with them.
I know it's been discussed here in the past in the HiPo section but can't find it yet searching.
Mongo
