Crate Motor? Identification...

I have an alleged 350 Crate motor in my Monte SS.

Non center bolt valve covers, timing gears instead of timing chain (most likely installed by previous owner)

And the following numbers stamped on block next to water pump;

1M0906

3VP

I haven't been able to get at the casting #'s at the bellhousing area, but I can distincly see alrge initials "GM" and some casting clocks...

Anyone out there that can at least verify this is/was a 350 at some point? All I've found so far is the following excerpt from Chevy-Camaro.com;

"Target Master/Goodwrench crate motors will have a serial number something like "1M1234VB" or "1MO1234VP" or even "2M1234VB" or something along those lines. It is only a serial number. There is no way to decode the horsepower of the engine."

Thanks!