There was some pinging at idle before I adjusted the new vacuum advance per recommendation for my distributor (D1AF-12127-HA as replacement of original that I believe was D0AF-12127-V), no more pinging after.
Stiffer PS in parallel parking (when hot) is not resolved, but I can live with it since PS works very well in Neutral (1000 rpm) even at complete stop, regardless of coolant temp.
Any comments as to how MPG could be further improved?
I’m late to the discussion, could you fill me in on the timing you are using, and type of carb, engine modifications. What engine size ? If we are talking about a small block ? I bet you can get over 20 mpg on the highway with a little effort. I’ve gotten nearly 24 mpg average mph over a 1,600 mile trip and never once went under 75 mph on 2 lane seldom traveled highways in west Texas and eastern New Mexico. I had several things in my favor: 3.00:1 gearing , a vintage Paxton supercharger, and a very lean cruise circuit thanks to an AEM fuel / air ratio meter which I had permanently installed in my '66 GT350
The base early 1970: 351W 2V with 2100 carb, FMX & 2.78 ratio. # match drivetrain with replacement carb. (D4PE EC), distributor (D1AF-HA) and dual advance (from NAPA - adjusted per instructions for the distributor). Also new cap, finger, condenser and new points every spring.
Initial timing unknown for sure, done by ear since degrees scale not visible anymore on balancer, but is believed to be close to the recommended 10°.
Choke thermostat adjusted on the lean side, close to the last mark. Thermostat is 195°F, no overheating. 3 port vacuum control vale sitting on the coolant stat is old but not know if original or not.
Had a 180 miles ride yesterday at 50-55 mph in country roads, fuel needle sits half way, MPG looks promising for the next fill…
a 2.78:1 gearing should be getting you close to 20 mph on the highway, if not over it. What is the diameter of your tires, and width ? The diameter needs to be over 25" and the width no more than the 225’s for best gas milage. 235 and 245’s will hurt the gas milage.
Often a light emory cloth rub on the balancer ring or pulley will reveal the timing marks. Since your timing marks are obscured, my only other suggestion would be to advance the timing slightly until you get some pinging under moderate acceleration up a light incline, then back it off until the pinging disappears. The more advance you can safely get, the better your gas milage will be.
Tires diam. 26-26½", width 215.
MPG at fill today = 18,5. That is huge improvement from 13,4 MPG last week! Will attempt to reveal timing marks next fall to get real figures.
In the mean time gas smell is less than before which seems good to me, however there is black smoke coming out of the exhaust on cool start and/or when I floor it to kick down… no hesitation tough. Why? Fuel mixture too rich?
Yes. Could be too rich. Cause of that might be several different possibilities.
Power valve bad, float level set incorrectly, choke not pulling off, dirty air cleaner, jetted incorrectly, etc.
