Jump to content

Vacuum advance on high c/r BBC


72 LS5

Recommended Posts

I know this topic has been touched on before.

 

But specifically on a high compression Big Block, is anybody running vacuum advance?

 

I always ran it on 454, but it only was a 9 to 1 motor. That extra advance really gave it responsive part-throttle acceleration. With the 10.6 to 1 502, I'm not sure if there will be harmful detonation that may not be detectable. All my mechanical advance is in by 2800 rpms. Chevy recommends no vacuum advance on this motor - so that probably answers my question. Just curious what others are doing. Was there vacuum advance on the old 11 to 1 solid lifer 427s and 454s of the late 60's early 70s?

Link to comment
Share on other sites

I'd hardly call 10.6:1 "high compression". I would run it. Just keep it to 10 degrees and have it come off at a higher vacuum if your worried about it. Lot's of places have 93 octane, another thing to help you sleep at night.

Link to comment
Share on other sites

Yes I would run it also, get an adjustable advance can so you can limit the advance if you run into ping.

I run one on mine for cruising, and I am at 11.4 to 1.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...