I don't usually have much to say about other's designs since I can't see inside your head to see your vision. I do see a few things, mostly related to reaching your goal of 800#. you have big steel where it isn't needed. the first is those big tubes running down the center of the car. Space frame cars don't need that extra weight IMO. You also have excess pieces that could be shortened and/or simply removed. Every oz must be considered in order to meet your goal. For some inspiration, I would recommend you take a look at some Formula Vee designs where the minimum weight is now 1025 pounds with driver.
Is this a street car or a track-only car? If a road car, most states have a rule that the chassis or any other part of the car cannot hit the ground if the car is resting on one rim. I see your lower chassis rails do not meet that requirement as drawn.
I see most all new posts and enjoy seeing others' visions move along. I look forward to seeing yours completed.
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Chuck.
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