Do the LG 21700 cells have a high enough current rating? They are rated for 7.3A.
An LEV50N is capable of 300A continuous (https://pushevs.com/2015/11/04/gs-yuasa ... vs-lev50n/
). You would need 41+ of those LG cells in parallel to be able to deliver a rated 300A. I don't think there is enough room to replace each LEV50 with 41 21700s. A practical maximum I've seen is in the neighbourhood of 20x21700 per LEV50 using this circle packing calculator (https://www.engineeringtoolbox.com/circ ... _1905.html
Unless we know with certainty what the maximum current the car will draw under any circumstance, I'd only be comfortable replacing like-for-like as far as battery specs are concerned. Lower amperage cells have a higher internal resistance and heat up more under load (and charge).