I agree with toulebag. I would allow $2,000. Some will depend on what type of manual you want. Obiviously a 3 speed tranny ($100-$200) will be cheaper than a four, five or six speed. Your engine size may affect cost. If your running a six cylinder, you can get by with a cheaper (lighter duty) trans, than a hi-performance small block or big block. You will need bellhousing, flywheel, cluch, clutch fork, tranny, mount, clutch equalizer bar, pedals and supports, shifter, maybe driveshaft and/or yoke, plus various small hardware. Used pedal setups getting harder to find. Some parts availl. new. Moderate job for experienced mechanic. Might be easier to put shift kit in your C-4. www.texasmustang.com for ideas on part costs.

About 2 Grand