Rebuild cost for the engine was very reasonable. I live about 60 miles due south of Reno, NV which allowed me to use a very reputable shop in Reno to do the rebuild. I brought them the complete engine (which I had pulled out of a 69 Camaro that was being parted out back in 1994) and they gave me back the complete engine (from the intake down to the oil pan) completely assembled and ready to go. In addition to being one of the finer shops in the area, everything was performed in house from the intake to the oil pan. Nothing was sent out. They handled the block, cylinder heads (including opening up the intake valves), machining, balancing, etc. Total cost was less than $2,000. There is an advantage in this area in that quality work is available at a reasonable price due to the high interest in the hobby in this area. I wouldn't expect much difference one way or the other between a 307, 327, or a 350 from the late 60's. All are basically the same engine.
As far as the spin on oil cannister, that went away at the end of the 1968 model year. In 1969, the cannister was replaced with the spin on filter and the oil fill was relocated from the front of the intake manifold to the driver side valve cover. PCV / crankcase ventillation routing was from a seperate filter in the air cleaner on the passenger side, through the passenger side valve cover, through the engine, out the driver side valve cover / PCV valve, to the connection in the back at the base of the carburetor throttle body. Guess my point is, if you have a 69' 327, no oil cannister - it will have a spin on filter and the oil fill is through the driver side valve cover. I've never used one, but I have seen adapters to convert from the cannister to the spin on filter. I believe all you do is screw the adapter plate on first and then the spin on filter mounts directly to the adapter.