The recommended timing values are merely to meet emissions requirements - they really ruin your performance. When a friend and I did the timing on my '79, we both agreed that the "suggested" timing (O degrees) was so absurd that the car wouldn't even run properly at idle!!!
Here's how you do it. Since the MB balancer has degrees on it, this is easy.... You want the "all in" timing to be about 36 degrees BTDC. By "all in" we mean the timing value when the engine is at higher rpm (generally about 3500 rpm), the point at which the timing advance is no longer advancing. (Be sure the advance mechanism is actually working.) I know this sounds radical to some, but it's how hot rodders have done it for decades!
Get a helper to rev the engine while you work the timing light. Have them increase revs to the point where the timing mark stops moving. Dial in 36 degrees BTDC. (Obviously, you should do this rather quickly. Don't take several minutes to figure it out! Repeat as necessary.)
Once you've dialed in this timing value, you need to drive the car and check carefully for any pinging. If there is pinging, back the timing off a couple of degrees and try again. Repeat until satisfied.
Need I mention that my 450SL goes like a scalded cat running from the bathub?
