This is my first carb car it's a 67 cutlass with a 425 and a holly 750 double pumper with hei edelbrock heads has some kind of cam in it idk previous owner wasn't to clear. I would like to try and tune it a little better but carbs are way before my time I've only dealt with efi growing up. Was wondering if anyone had a vid recommend or a write up to read on my car. I think I have the basic knowledge but I'm nervous of messing it up. Like are thete numbers my car should be at or is it different for every set up? Like what should my vaccum be at my idle timing what is a dwell angle? Any advice to help my try and tune it up better. I really want to double my gas mileage I would be so happy if I could get closer to 12 mpg. Thank you. In advance for any info you can share to help me.

 

Start by purchasing a wideband O2 gauge setup. I’ll bet that Holley isn’t jetted right for your combo.
Next set timing in the 10-12* range at idle with no vacuum advance. Then check the total timing. A good safe number for total is 34 at 3200 rpm or so. Then go from there

 

I would first write down your current timing settings at idle (initial advance) and how many degrees at what rpm it stops advancing (total mechanical advance), and idle vacuum reading. You'll need an adjustable timing light, tach/dwell meter, and a vacuum gauge. Dwell is n/a its for a points type distributor.

These are a good read:
http://www.crankshaftcoalition.com/w...ance_Specs.pdf
https://performancetechnician.com/pd...age-Engine.pdf