Truck Repair: distributor problems, vacuum modulator, vacuum leaks

Question
I have a 1986 Dodge D150 1/2 ton pickup. it is 2 wheel drive with an automatic transmission and it has a 318 V8 engine with a 2 barrel carb on it. my question has to do with how its running right now. my truck seems like it has a loss of power. I have recently checked my fuel and air filters and they both are good. I've also just rebuilt the carb. I was told that year of truck has a spark control computer that controls the timing on it. and I was also told that since my truck no longer has any emissions on it, that the computer is not able to control the timing. and I was also told the only way remedy this problem was to put a pre-emissions distributor with electronic ignition and vacuum advance in it. then he said that once I replaced the distributor and hooked up the vacuum advance on it, that my truck would run a lot better and I would regain that loss of power. right now my truck is running pretty good, except for the loss of power and my choke isn't working right either. but other than that the truck really isn't running too bad but it was running pretty good until about a month ago. about a month ago, my truck had hardly any power to it. it took the engine forever it seemed like to rev up and to gain speed. that is when I decided to rebuild the carb. and that helped it a little bit, but it didn't fix all of my problem. then I reset the timing on it and that fixed a lot of my problem. but my neighbor said it should have more power and run better than what it is right now. and thats when he told me about the spark control computer. any advice you can give me will be greatly appreciated.

Answer
Hello Justin,
I have never replaced one of those distributors with a regular one, although I don't say it may not be a bad idea.
But I don't recall the electronic spark timing being disabled by the removal of the air pump, egr valve control, cat converter, or anything along that line.
I would check for vacuum leaks, including the egr valve, brake booster, vacuum modulator on the transmission, A/C controls, vapor canister, etc.
All hoses, also, and the PCV valve.
Then advance the timing till it clatters just a tiny bit upon acceleration.
Make sure the choke opens completely, the heat riser in the right exhaust manifold opens completely, and the accelerator pump in the carb squirts in a healthy spray of gas in each bore when the linkage is operated.

A swap to something like a Mallory distributor could help, and help a lot, but I have just never needed to do it.

Van