Pin Weight and Additional Batteries?

[sjturbo]

Not being the sharpest tool in the shed I am seeking some advice! Scenario: 2010 316RL. Comes with one 12v battery (weight?), in the front recessed storage compartment near the front elect. jacks. Replaced 12v with two Crown 6v (~140lb). I would like to add two more Crown 6v to increase Ah. I have not weighted batteries but specs say about 70lb. So total of ~280lb total. I have a battery box that will accommodate four side by side and intend to center it. Front compartment will need additional bracing I believe to support additional weight. Are there other considerations I need to take into account. Inputs will be greatly appreciated.

[sjturbo]

I believe I have figured it out. Thanks for all the views.