[matto68]

Can anyone give me a run down on how to set the timing on a 350 using a vacuum gauge.. I'm having a difficult time finding the right 6 3/4 harmonic balancer for the engine. It’s a GM 290 hp crate. It runs great but the timing mark is off about an inch... I have the bolt on timing tab for a 6 3/4 balancer supplied with the engine. It’s at the 2:00 position. They recommend using an 8" balancer but I have clearance issues with my power steering pump. Once again the engine is running great I just want to make sure the timing is set correctly.

 

[HarleyD67]

First off how do you know the timing mark is off an inch? Did you degree it with a piston stop? If it is off the first thing to do is find TDC and mark the timing tab and or the balancer correctly. Then you can start to check the timing. As far as a vacuum gauge. I've never heard of using that to set timing. You tune the carb with a vacuum gauge to get the highest reading, and may need to reset the timing after you adjust the carb, but the it has nothing to do with setting the timing other than having to reset it.

 

[JD4020]

You are disconnecting and plugging the vacuum advance line on the distributor, right? That would put you off about an inch.

 

[matto68]

I have the vacuum advance disconnected not plugged. That might be the problem?? I'll try that tonight when I get home from work.

 

[matto68]

I think my timing is off because when I installed the hei distributor I couldn’t advance the timing because the distributor hit the firewall. So I moved the distributor 1 tooth and the engine fired right up and runs great. I did find TDC and I have the wires connected to the cap correctly. It wouldn’t run if I didn’t. I have the right balancer and tab per GM performance parts. The vacuum advance is disconnected and pluged. As far a setting timing using vacuum, guys do it all the time I just didn’t know the right procedure. I found this on a corvette site. http://forums.corvetteforum.com/showthread.php?t=587000