Vacuum Advance and why to use it on the street

[WILMASBOYL78]

I will certainly bow [img]<<GRAEMLIN_URL>>/worship.gif[/img] to the experts and can only offer my &quot;real life&quot; experience. We have a number of L78 Novas which are street driven and one which is occasionally run in the 1/4. They all have factory points distributors...we run vacuum advance on all of them. The engines all have the factory L78 cam, 11 to 1 pistons, big heads, etc..basically stock L78 motors...nothing tricky. For fuel we run a mix of AV Gas or race fuel mixed with 93 pump gas...no issues. Only one of the L78 cars has a &quot;curved&quot; distibutor...our black 1970 TH400. I have never tried running the cars without the vacuum advance...never saw the need to. Most of the factory BB solid lifter motors (68-70) had the #355 unit which had 15* advance..this is the vacuum unit that is in all of our stock distributors.

Again...my info is directly related to driving these cars for many years and knowing how they run. I can't comment on how other people's cars run or perform...only my own. I maintain that &quot;fuel alone&quot; does not determine the results related to vacuum advance or the lack of it...there are many factors that impact performance and tuning.. and each situation is a little different.

wilma [img]<<GRAEMLIN_URL>>/[/img]