tranny changing

i have a 68 camaro with a 3 speed auto tranny and i wanna change it to a 4-speed standard and i was wondering what parts i need to make this a succesful change

The most difficult part for this is the engine.
A Chevy manual-trans-equipped engine have a hole drilled in the rear of the crankshaft to insert a pilot bushing. Without one, your clutch will not work.
Generally, engines bolted to automatic transmissions at the factory did not have this hole.

You cannot drill one yourself. A machine shop could do it but they would need the crankshaft removed from the engine.

If you are very lucky, the engine already has one but you would have to remove the transmission to take a look

Otherwise, you would need the transmission itself, bellhousing, clutch disk, pressure plate, flywheel, a set of clutch and brake pedals, with their own mounting bracket, clutch linkage, and probably a new transmission crossmember, rubber mount, and driveshaft. You will also need a template or pattern to cut the appropriate hole in the floor for the shifter.

Seeing as original 1st gen Camaro parts like this are very scarce, expensive and old, why not upgrade to a more modern 5 speed transmisson?

The '68 engine should have the recess for the pilot bushing, the newer ones didn't have them, not sure of what years though.

I've done similar swaps using junkyard donor parts, they are available if you dig around online. The pedals and linkage are all available as aftermarket pieces too. You will probably need to have a tab welded onto the frame for the cross shaft ball pivot. Those I've made up when I needed them.

Bob