whats the deal with the shifting on this car? it seems like it only has 3 gears? does first shift as soon as you start moving or what?
Yes, the first shift happens quickly.
In line 6 (not sure how many CI)- can anyone tell me?
In '70, a 2.5 liter with single chain and 9:1 (or possibly 8.7:1) compression for the 250 sedan.
Has 2 zenith carbs... WHAT IS THE DEAL WITH THEM? I saw someone call them warpomatics or something? are they good carbs or what?
Excellent carbs, if either original low-mileage or straightened out by an oldtimer MB doc. If neglected (or hacked) they can indeed warp, and the reality is many thousands to restore them back to factory condition. Not all parts are available. Most give up and buy Webers. The Zeniths are happy to supply endless punishment unless they're treated carefully.
my dad has two rebuild kits for them...
Throw them in the trash. I went down that road years ago and ended up doing it over with the correct MB parts. The accelerator pump "cups" for the plastic plungers are a joke, they slip off the plunger every couple days and make you pull your hair out wondering why the hesitation is back. Some of the included gaskets are junk, and/or incorrect and will cause problems.
I was trying to tune the larger air screws on the side of both carbs to get to it stop hesitating. He tells me its the accelerator pumps but im not sure about this.
Accelerator pumps are a likely culprit. The nozzles themselves may also be plugged, and need to be squirting in the right place. Vacuum leaks (almost guaranteed) and carb synchronization are other common problems.
anyone have a base air screw setting for it?
About 2 turns, but the reality is there are a million other things to check and correct before trying to dial in the idle screws. Ideally it should be done with a CO meter, matching the RPM drop between the 2 carbs as per the factory setup info
also what are the really small adustment screws for? they seem to be seized?
You're probably referring to the little screw plugs for the factory test ports. Usually they are left alone, but they make a good place to screw in a couple of fittings for synchronizing the carbs with a manometer - far easier and more accurate than the uni-syn style tools.