Interesting how he went from a pinto to a fairmont. I also have one of each, but I'm no Bob Glidden.

"Weight break for the longer w/b cars."

Correct.  That is also why Gapp & Roush went to the 4 door Maverick and Wally Booth went to the Hornet from a Gremlin. Before they gave weight breaks virtually every Pro Stocker was a big block.  And on a level weight break the Hemi simply dominated.   I don't know that the weight factor lasted but a few years at least regarding wheelbase. Also, as the cars got faster the longer wheel base might have made them more stable. So, regardless of any weight advantage stability might have been a consideration.  I recall in that era Don Carlton dying in a crash with the Motown Missile that was a Plymouth Fire Arrow with a hemi engine.  An enormous amount of power for a very short wheel base.

Tom