Casting #3849309 64-67 Chevy II
This "309" is an aluminum 153 tooth bellhousing with 4 5/8"center hole and the example shown has no z-bar provisions. The clutch fork hole is at the 7 o'clock position, and the fork stud is lowered to be inline with the center hole.
The casting is for left or right hand drive cars.
Transmission mounting is four 1/2"-12 tapped holes.
The part number is on the unused clutch fork knock out.
There is a GM insignia in the middle "rib".
This view shows the straight starter side common with the 153 tooth flywheel bellhousings.
The above view of the inside shows the straight line from center hole
thru fork stud to the fork hole.
It is also visible how close the lower drivers side transmission mounting hole is to the fork hole. This makes the fork boot unique, because it needs to be notched to clear the mounting bolt.
Factory correct applications are your responsibility.
GM made part and part # changes with no rhyme but a reason (no production interruptions at any cost).
Application charts are for replacement parts that were available at the time of parts book printing.
My observations come from the parts I have in my collection or other reliable sources. Your parts may differ.
If Factory correctness is your goal, do more research, join car clubs and forums and buy an assembly manual if one is available for your Project Car (you wont be sorry).
This is a fun and interesting part of the hobby!