I Need Advice
 

My grandfather gave me his old 68 benz 280SE, but it has been sitting for about 15 years. Anyone have any suggestions on what to do? It's mechaniclly fuel injected and they only used this engine for a couple of years. Would it be worth repairing or should i part it out? Any input would be greatly appreciated.

Seems like you're really restricting the choices on yourself.
You don't really say why/what needs repairing. Most important is the overall condition of the body. If it isn't rusted out at all and the interior is fairly decent, you could fix what needs repairing and have some fun with it. If that's what you're into, that's another thing, are you interested in old cars in general and Mercedes in particular?
If it is worth repairing is up to you, people go to great extremes to repair vehicles that aren't nearly worth the cost and effort.
If the car is in generally good shape, you may be wiser to just sell it as-is rather than parting it out.
If you think you can fix it up AND MAKE MONEY ON IT then for Cripes sake SELL SELL SELL it!!!!! You DON'T want to go there. Here's the tip of the year for ya: It DON'T work that way!!!!!
Gilly

I like this car a lot. Good old Benz... I am mechanically inclined so if I were you, I would definetely give it a good service, change fluids, flush fuel system, give it a good engine clean up, replace battery, possible cracked spark plug wires, spark plugs, check ignition rotor and distributor for possible cracks. Finally make sure that fuel system develops fuel pressure and fire it up. I would also considering droping a couple of bottles of fuel system cleaner (Techron) the first time I would fill it up at the gas station.

IF THE ENGINE IS SERVICABLE (GOOD CRANK AND HEAD) there are a few thousand 280sl owners out there that will snap it up for a nice price.
that car is worth more as parts than as a whole.
mf

If you are going to drive this car, it would be a smart idea to flush out and replace the old brake fluid and replace all the rubber brake hoses (one per wheel).