I have a original C hump.
I use it as a pattern to convert the b
I can give a fairly accurate way of doing the surgery.
But, BUT, before anyone gets all pumped up and Gung ho about 4 speed,
source a bellhousing, flywheel and clutch. And a transmission.
Then hunt down the torque tube, or Z bar in Chevy talk. Plus find or make the bracket that welds onto the stub. And consider getting this bracket in the right place.
Keep in mind you need clutch and brake pedals and brackets. This is not complicated if you find a parts car or wreck and can get ALL the pieces.
So the hump is one of the easier pieces in the puzzle.
To be fair, a few c bodies have been converted. But dam few.
As time permits I'm doing either a 66 300 or a 69 Monaco, I'm having a hard time deciding