WHAT AM I MISSING HERE

forgive me for being naive or uninformed here, but I need to know if this proposal is good or bad. I have a property for sale that is best suited for handyman, rehabers or builder ( needs lot of work) and I am looking for 300k new const houses are going for about 700k and rehabed for about 380k. what if I proposed to for an example to a builder to build a new const AT HIS COST from start to finish. at the closing when sold I take my price and he takes what ever profit he makes. same deal can be worked out with rehabers als at a smaller scale.
what im a missing?
what are the pros and cons of this deal?
and please who can tell me what is the builders cost per sq ft to build? would like to know the inside scoop
this is in chicago
thanks and please excuse my misspelling

Are you asking about taking a 300k property, demolishing the old house for a new construction house to be put up and sold in the 700k range?

A few commas and periods.

Those two keys and apparently the “shift” key appear to be malfunctioning…LOL

Keith

Despite the wealth of knowledge I have witnessed in forum, Glad to see sense of humor isn’t lost. Ruthless I say, ruthless.