2nd gen tundra payload rating

Okay so here is a crazy one. Using the 2018 Tundra as a benchmark (last year with factory trans cooler), the tundra weighs ~5500lbs and has a payload of ~1500lb (using easy rounded numbers here). Now the Seqoia on the other hand weighs ~7500lbs and still has a payload rating of almost that 1500lb.

So now work with me here, if you are crazy and already planning on doing a frame stretch to get the Crewmax with a 6ft bed, and rather than stretching the Tundras frame, instead swapped a Seqoias fully boxed frame and stretched that (since the first major issue is the Seqoia has a shorter wheelbase and thus frame) would it not stand to reason that the Tundra should then be able to handle that 2k difference and have a payload of over 3,000lbs?

Other than possibly suspension, is there any other difference in the platforms or reason that isnt technically possible?

 

I like the theory but I'm seeing a Sequoia's curb weight at about 6,000lbs with 1,300lbs payload... So not so much difference to the tundra. The biggest problem I would think would be the independent rear suspension and cab mounts. Otherwise engine, trans, and transfer case should all be in the same spots from what I know, but don't hold me to that

 

I will have to double check the spech sheet I was reading.