I have always fancied Edelbrock carburetors and I've got one on my 350 engine. Now that I have driven her around 3800 miles and the average consumption is around 19 litres per 100 km(~12 MPG), with mostly in highway. That seems to be just a little bit too much even for a 40 year old engine. So first thing that I thought was to tune the carburetor and see how's that goes. I started to read about tuning and such from the net, and I found one thing that might explain consumption. Vacuum advance for distributor is taken from the carburetor and there are two ways to take it, so called manifold vacuum and ported vacuum(also known as timed vacuum). I've searched lots of threads and pages about it and founded that manifold was in used before energy crisis and emissions. After that they made this quick-fix, where they take the vacuum advance from ported, which is located just above manifold vacuum port. Other thing that I've founded was that ported is also used when you have manual transmission and manifold vacuum is in use if you have automatic transmission. So, I had mine set on the ported.
Ported one is on the left and manifold is on the right.
So I tried to change that, but the vacuum hose was to short and I had to buy a new one, which wasn't expensive and that was done. At first I've noticed that idle is little bit higher now, but engine seems to be responding much quicker and better. Second thing is that I noticed that air filter is quite dirty, which could also explain risen consumption also. But I thought that first I just drive around with the old one and see how that vacuum advance thing works out, but then again...
I have ordered new filter and I am about to put Kelly back to garage for the winter and there is still few hundred miles to drive before that and saving every drop is always better and you can drive for further.
