You have an interesting casting number!
It is definitely a 1969 engine.
Your casting number, 3956618, was used to make three engines, 302, 327, 350.
The 302 was 290 HP, 4 bolt main Z-28 Camaro engine.
The 327 was 235 HP, 2 bolt main used in full size cars, Impala for example.
The 350 was 250 - 350 HP, 2 or 4 bolt main, used in various cars.
Now, if in fact your engine is 355 cid, it has been bored +0.060", the max a SBC can be bored, safely.
So, it's kind of academic what it started out life as.
:shock:
The chances are about even (from the casting number) whether it's a 2 or 4 bolt main.
Chances are, it's a 4 bolt, if in fact someone has spent the money to have it bored and decked.
The missing numbers, Engine Partial VIN and Engine ID Code would help figure out what it started out life as, but it is what it is, now.
The partial number you've given is the Engine ID Code, V0113.
V = Flint (plant where the engine was made), 0113 = January 13 (of 1969,from the casting number), what's missing here is the Engine Suffix Code, it would look like, CLJ, or CTY, so the entire number would look like, V0113CTY, for example.
The Engine Suffix Code tells the rest of the story, year, displacement, HP, car it was in, transmission.
So, without opening the engine, a safe bet is, it's a 4 bolt main, hopefully 355 cid (if it's bored) and hopefully, it will run strong for you!
Hope some of this helps!