Go back to post #7 on page 1 and look at the EFE valve. If your valve is like the one on my '85 454 with no vacuum applied, the valve is open. My truck is currently getting a new engine and I can verify the valve is open with no vacuum. I'm not sure if your set up is similar.
It's been 35 years since I've had a vehicle with the old bi-metal type heat riser. I believe those are closed until the spring heats up enough, then the valve is open. On my '64 Chevelle I had back then, I wired it open as it sounded like an exhaust rain cap on a semi.
The '85 system is reliant on all of the vacuum lines, check valves and ported vacuum switches working correctly. If there are any vacuum leaks, it can cause poor performance. Due to the fact I have to go through California's bi-annual smog program, everything has to work on my truck. I have replaced every vacuum operated engine part on my truck, even the vacuum motor in the air cleaner snorkel. I also found during this rebuild process that both my secondary vacuum pods on the passenger side of he carb were bad. I had to replace all of the vacuum lines since all the OEM molded connectors were dry rotted. As you can see from my emissions label, there's a lot of places to have a problem. One thing to check also is make sure the check valves are facing in the correct direction. Many are one way valves.
You must be registered for see images attach