when i ordered mine form LKQ/keystone i ordered the one for hd cooling and i got the 34? inch one. my truck came with the wider one but with the hd it is now as thick as the tanks a apposed to the stocker that was half the thickness.
so if you want better cooling just order the wide one with all the options. bolts right in on mine
so if you want better cooling just order the wide one with all the options. bolts right in on mine