Need Help with New Duplex Contruction Deal Analysis

[Munish Ashat]

Hello BP community!

I am looking into building a duplex and need some insight on this deal. The builder is my neighbor and owns a piece of land in our subdivision. The land is 0.3 acre, and duplex will be 2000 sq ft and 2200 sq ft. Each side will have 3 Bed, 3 full bath, walkout basement, LP smart siding, LVP flooring throughout, 2 car garage. Builder will carry the loan till possession. Once done based on comps in my area i can rent them for $2400 each. The land costs $90k and construction will cost $600K. 

Any and all feedback, tips, suggestions are very much welcome and knew coming here asking you all would be a huge help.
Thank you!