OK - so as most of you know - I transplanted the engine from an 84 300SD into my 240D body. In one of the threads i posted, someone mentioned adjusting the ALDA to improve 1st gear take-off. I did a search about this, and it appears that the 240D won't have the proper thing on the firewall for the ALDA tube to hook into. (sorry I don't remember the right term...) And consequently, that the turbo probably isn't doing anything because nothing is hooked to the ALDA. Is this right? Turbos and all the associated stuff are new territory for me - so please be as basic as possible. Thanks in advance for your help.

Not a dumb question at all.

The reason that there is no "overboost protection valve" on the firewall of the 240D is the fact that the vehicle was never turbocharged, and, therefore, had no need for fuel enrichment.

So, you should probably find the overboost protection valve from the old vehicle, if you can, and mount it to the firewall on the 240D. If you can't, it's not absolutely necessary. The valve simply cuts the fuel enrichment if the boost exceeds a prescribed limit, so that the pistons are not cooked. The boost can't get up the this limit, unless the wastegate is not functioning.

So, the line from the back of the manifold goes to the overboost protection valve and a second line goes from the overboost protection valve to the ALDA on the injection pump. The ALDA is the device that actually performs the fuel enrichment. It senses manifold pressure and advances the rack accordingly.