I have an 87 350 pretty much stock with a 4bbl carb and HEI dist. This is a street engine that will never see the track. I wanted to install lighter spring into the HEI distributor. I remember reading somewhere that the total advance should be measured when using low octane fuel. What is the best total advance and what rpm to you measure it at? Thanks

 

As long as you're going to play with your distributor, give this a read. Sorry, it's a lot to read, but there's a lot of good info in there: Distributor Tuning

 

Also try holley.com in their tech section, also berry grants site, they have a few total timing tech tips there