Iv seen similar casting. GM's 3720991. Also have one in the front under passenger head of 0257665f56ge. The ending of g iv seen on the forms but the ge iv never seen anything about? What do you guys thank. Sorry but I could figure out how to post picks from my phone. This motor now has a two quad car's border 30 over mild cam. I'm trying to figure horsepower so I can put the right gears in the rear as of now they are very low.