My brother brought me his slug of a gas-burning pig, 77 with a 360/727.
That 2bbl carb on there was extremely lean, and there was no way to put a timing light on the engine.
So I pulled the doghouse and drilled a hole in the bellhouse. Then with a piston stop, made my own mark right on the convertor. After that I could read the timing with my dial-back lite. So I made a timing map, both with and without the Vcan. The timing was extremely sluggish, and it wanted to ping just about all the time.
First
Make sure your ECU is getting the correct voltage. My van had a nearly-blown bus-bar on the ammeter, so not much was getting thru; that was a hard find. I fixed it.
As regards this van;
The 360 did not like a lot of initial.
So I scrapped work on the D, and went to work on the carb first. Man, every circuit was lean. So I pumped it up, then worked on the timing, then pumped it up some more, then more timing going back and forth until she would almost pop a wheelie! Ok slight exaggeration.
Then I pulled that sick Vcan off there and modified it for more and more cruise timing.
I put a two-stage curve in it, that was fast to 2800 or so, then slowed right down to all-in by I forget maybe 3600, I know I had to slow it down pretty hard. I think the idle timing was around 8/10. As to the cruise timing I forget but it was a lot. This was a long long time ago, so the details elude me.
Oh yeah, after I got to a certain point, I started to suspect a restricted single exhaust, so I tested the system. It was less than 4psi at WOT thru the torque-peak so I left it alone.
When I returned the van to my brother about a month later, he was so impressed that he showered me with cash. It turns out the van had already been to several shops in his medium-sized town, and no one had been able to get a thing out of it. He was one happy guy. Even the hiway mileage had improved.
After that, every time we met, I don't think he ever failed to mention that job.
Not much help, I know, but you get the idea.
