390? 428?

So I recently purchased a 1970 ranchero that I was told had a 428 in it. I rushed home with my new treasure and pulled the motor c6 trans and 9 inch to freshen up and install in my 1970 Torino gt. As I was cleaning and checking parts and pieces here is what I found. The casting Number on the block was a mirrored 105 which gave me question because I thought that at the fe motors were supposed to be marked 352. This caused me to get on the computer and look up casting numbers instantly I was kicked in the guts when I realized this was possibly a 390 truck block. I pulled the number on the heads again finding they were 390 heads C8AE – H. Setting on top of the heads are a set of Harland sharp roller rockers. This prompted me to pull the oil pan to find a 2U stamped on the crank and what I believe to be 390 heavy duty truck rods attached to the crank. In measuring the bore size I found it to be 4.130. The intake is a Edelbrock Street master with an Edelbrock 1411 carburetor sitting on top I am unsure of the cam Size but has a nice lope as it idles. Pistons appear to be cast nothing special. I'm looking for input on what in the hell the builder did here I am fairly unfamiliar with ford FEs previously dabbling in mostly Mopar any help would be appreciated any ideas possible horsepower and torque numbers and whether this thing will hold together the way it's built it appears the motor has very few miles on it and the person I bought it from was no help as to what or who the builder was thank you in advance.