Fuelly Forums - 1969 Datsun 510, expanding project scope

My 1969 Datsun 510 was a 5-year ?restomod? project that was put back on the road in May of 2008. Since that time I have driven it over 14,000 miles. It was built with occasional track time in mind (big brakes, overkill cooling, adj. suspension, etc.) which makes it an interesting and perhaps unlikely ?crossover? into thinking about high MGP. However, weighing in at only 2000 lbs, with a modern EFI motor and fairly small frontal area (although pretty ugly Cd), there?s potential. I have recently swapped the gearing in favor of better highway FE by changing the diff from a 3.90 to a 3.54 (?07 STi Torsen LSD R180) and by changing the 5-speed to a 6-speed (S15 SR) with a 0.767 top gear. OK, sure, these were both performance oriented changes, but at the same time they took me in the direction of better MPG. When the weather is OK, I use it to commute 82 miles a day, 80% highway, so I will have repeatable conditions to test future FE mods.

There are several things I will consider changing to improve MPG. One of the more fruitful would be tires. I have only used a performance-based tire (Azenis RT-615 200UTQG & Potenza R11 180UTQG) which are quite wide and sticky, the polar opposite of LRR. This switch alone, I imagine, will show a bit of an improvement, as well as pay for itself due to the very short life span of my current tires (<8,000 miles). Other potential mods would be a programmable ECU to maximize efficiency (Nistune, AEM EMS or similar) and perhaps some aero mods if I can make them basically invisible.

I have tons of gas receipts and fuel data, but I?ll just start my mileage log as of now and go from here. I wish I had started my log before the gearing changes, because it would have been really cool to see the bumps on the graph.
Here?s a few pictures of the build?
https://www.flickr.com/photos/2518602...0465162/detail