yes one by oil filter and one behind the distributor
Most SBC have a port next to the distributor.
There is a 1/8"npt port on the back rail of the block near the distributor hole.
Ports the fumes.
Next to distributor, on top of the block, at the very back of engine (usually).
Near where the oil filter mates with the block and there is a port on the top of the block just behind the intake near the distributor.
It hooks to a vacuum port on the intake manifold behind the carb.
look for the port with the black cap on it, it's the low pressure port.
One in the intake, near the thermostat, and the other one, in the upper port on the water pump.
The low pressure port is the one on the accumulator (the canister). The low pressure lines are the bigger lines and the high pressure are the small lines.
Chevy does not cast the block size onto the block. once you see a big block compared small block you will know the difference. at a glance with nothing to compare it to id say look at the head. small block heads have one exhaust port close the ends and two exhaust ports real close together in the middle. the big blocks exhaust ports are evenly spaced and not close together at all. If it is a 350 or smaller it is a small block. If it is a 396 or larger it is a big block except for the 400 which was made in both small block and big block configuration.
Yes and yes. The orifice tube is between the service ports.
If the intake is on it, Look at the back of it where the distributor goes in it and just behind the intake were it seals against the back of the block you will see a small hole in the top side of the engine block. That is the oil pressure port.