Chassis bracing

ocrj said
http://www.classicindustries.com/product/mopar/parts/mm8173.html

I'm a little confused by how many model years it appears to cover?

Me too. This is worth a call. I've seen some sources quote the earlier Valiants and Dart wagon at 106.5". Either way it seems to me that there is a one size fits all feature to the kit that isn't evident in the description or they left the * out of the description.

Valiant 63-72 ................108" wb
Demon/Duster/Dart Sport 108" wb
Dart wagon 63-66...........108" wb
Valiant 4 dr. 73-76..........111" wb
Dart (except as noted)....111" wb
Barracuda 64-69.............108" wb

FWIW: Torque boxes were used on the convertible and wagon models to stiffen the body structure. Considering the weight and non-interference with other stuff, if I had 'em, I'd use 'em,