Good luck with your 2V0 build. I think you can see the slightly unusual 2V0 cylinder porting, the exhaust is low at 38mm below the top of the cylinder. This should make the engine good for torque, and notice no decompression hole either.
The normal RD400 exhaust port is about 35mm down, but they made the 2V0 more emission limited.
I guess you are leaving the exhaust butterflies off, looks like they were removed before.
Carbs, reeds and airbox/filter? With standard (38mm, etc) porting there is not much point in going wild. BTW, remember the 2V0 carbs are weird, with the reversed Idle mixture screw set-up. We had a member on here a while back with a modified 2V0 and the carbs gave him some trouble.
So, interested what your plan is?
5port