Cool Dave’s 1973 Dodge D100 Club Cab

TT5.9mag said
Depends. What carb do you have? Post a few pictures. No need to get a new distributor just yet, you might just need a vacuum can. And let’s start talking in actual numbers here and narrow down the timing. What is the initial timing and what is the idle rpm? What is it at 1500? 2000? 2500? And so on. What rpm does it stop advancing at? With that info someone like @Mattax can plot a graph for you. All of this should be done with the vacuum advance disconnected and plugged.

Here’s the best picture I have right now for the carb, I’ll snap some more next time I have the hood open as there’s a few other things the service manual doesn’t offer much guidance on.

For the distributor I’m sure I could probably get away with just the vacuum can and I may take that route but considering the can was bad on my new part (thanks China) I may just buy one locally that should be better quality.

Mattax said
Just skimming through. It sure looks like an EGR valve on the intake. Off the top of my head EGR should be closed off when the engine is cold, at idle hot and cold, as well as at wide open throttle. Typcially they use a ported vac source and some sort of thermal switch usually in a coolant. vac diagram should be (was ?) in the engine bay. Some used a venturi vacuum signal. example diagram of venturi signal system

Some info on the EGR systems in the Master Techs series in '74. Can also skim back through '73 and '72 to see what is there.
https://mymopar.com/browse-mtsc-by-model-year-1974/
Knowing the engine has smog stuff on it, would want to see the carb and check the FSM or Sun cards to see what else it had. Generally trucks has less junk added to them compared to cars of the same year. Shop manual (cars) shows smogged 318 ought to be around TDC to 2.5* at 750 rpm. But that only works at higher rpm with the matching distributor curve. An earlier 318 with its distributor will be more like 5* at 650 rpm. Measure the rpms vs timing and we'll graph it.

I will get the book out again and reset the timing to factory, I want to say it specified somewhere around that 5* mark but I will confirm. In terms of smog stuff it seems like it really only has the charcoal canister which has all the lines disconnected to/from it and that EGR valve.

The last point to note for future troubleshooting too, this motor is not original to the truck. I’m not sure what it came from but it was swapped in around ‘05-06.

So questions..

1) Does the EGR need to be functioning or can I simply leave it capped?

2) Heat riser valve on the passenger side exhaust.. how do I confirm it’s working correctly?