Awsome looking Malibu...my first car was a 79' Malibu.

Anyways, The stock motor in a 78 Malibu could be a 267, 305 or 350...all of which are V8s but none worth messing with. Even if the car came stock with a 350, it would be a light weight block with junk for heads. It just isn't worth it. The 3.8T motors are some what easy to come up with and are made for a G body car just like the Malibu. So swaping one in is probaly pretty easy. The only thing that stands out odd to me is the fact that it looks like he used the stock Powermaster brakes of the GN/T-type Regal? The factory vaccum brakes are way more trust wrothy in my opinion than the PM's.