From what I have been able to find it looks like it will be the Mitsubishi 4G series but only the block. It appears that PSI is working with a joint venture company to have the blocks produced. Not sure on the rest of the engine components but most of those are available already. PSI does manufacture one of the very large GM engines them selves, can not remember which size, because GM quit making it. If you Google "PSI 2.0-2.4 ENGINES" exactly how I have it without the parenthesis the first 2 results should be a file shareholder website that has a PDF with a little more information in it from 2012.