For starters, both the 230 Sprint and the 250 Sprint used those manifolds, so that doesn't mean anything. The best way to tell the displacement of the short block is by the block's date code.

Each year's OHC is unique in one way or another, but it's easier to identify each one when you have another one to compare it to. You can almost always tell the year of the short block - and therefor the displacement - by the block date code. But it's easy and possible to make a 230 into a 250 by swapping out the crank. (They have the same bore.) The head's date code is under the cam cover, so unless the motor is apart you won't be able to exactly tell the year of the head, but there are ways to immediately tell the size (230 vs. 250).

For a quick check of the short block, the balancer is unique to each displacement and each type. (230 vs. 250 and 1-Bbl. vs. Sprint.) If there is no balancer, the crank snout is 1-1/4" for a 230 and 1-3/16" for a 250. The short block is completely the same between a Sprint and a 1-Bbl other than the balancer. The engine code will tell you whether the engine had (not has) a 1-Bbl head or a Sprint head.

For the head, there is at least one subtle difference for each specific displacement and year. Again, this is a lot easier to manage when you have another to compare it to, but from the outside you have ZERO chance of identifying the head as a Sprint head vs. a 1-Bbl. head. Along with the date code, the heads casting number is under the cam cover. You MUST remove the cam cover to determine if you have a Sprint head.

But, for the sake of argument, the cylinder head can tell you a lot about the size of the motor it came from:

1966 Only (and therefor a 230): Used less material around the freeze plugs on the head.

1966 and 1967 (230): The temp switch / sending unit is a 3/8" pipe thread. Unfortunately, this sender is almost impossible to find, so we ALWAYS open the threads up to a 1/2" pipe thread so that we can use the V-8 switch or sending unit.

1968 (250) used a 1/2" sending unit and the water pump bypass is external.

1969 (250) used an internal water pump bypass, a different water pump, and a different water pump pulley. Almost no one goes through all the trouble (except us) of converting an engine from external to internal bypass. Most people would simply eliminate the bypass which helps cooling and shortens the warm-up time.

Because these motors have been out there for 40+ years, it's impossible to tell whether any of the parts are original. You will have to have the cylinder head's casting number to be certain you have a Sprint head. However, all is not lost. It turns out that the 230 1-Bbl. head is remarkably similar to the 250 Sprint head.

I sent you a PM so that we can take this off-line and not bore the rest of the crowd here.