This looks like a DEON kit. Seen a few kicking around on Petrolheads for sale. Also seen them based on some Volkswagon donor but cant remember which.
The engine has just been spun round through 180 degrees and mounted in the rear, this results in a kind of "dog leg" box, shame really as he could have lifted the gear linkage from a Monte Carlo to get over that problem. Why he did not do that I dont know, but he used a Monte exhaust on it by the looks of things.
Nice looking finish to it overall though, so credit where credit is due. I wonder if how well its been put together and how good its electrical system is?