GM put the tank in the cab because it was the least expensive place for them to put it from a cost of installation on the assembly line perspective.
Unless you have provenance to prove that GM's choice to put the tank in the cab was to save cost, I think that it is just speculation. I'm not saying you are wrong, you may be right, I just don't understand how making a rear mount tank for the suburban/panels and a completely different tank for the trucks can be cheaper than just one tank for everything. The rear tank COULD have been used in the trucks but the seat tank COULD NOT have been used in a sub. It could be that they wanted to keep the tank out of the elements. Tin tanks under a vehicle have a relatively short lifespan. Seat tanks last as long as the truck. It's great to kick differing opinions and thoughts back and forth. It's how we learn and keeps a forum interesting.
Thanks
