How many miles per gallon does a 1983 El Camino get?

Answer 1

In March 2010, I bought a 1983 with the 305 4BBL E4ME Quadrajet and found it had the THM 250C with 2.56 posi rear. First highway mileage check surprised me at 23+ mpg. Lowest in over 6 months has been 19.55 mpg in mixed suburban/interstate.

Not sure why 2.56 ratio is in the '83 gas model. My old '83 sales brochure doesn't list it as an option. Everything I have found so far shows that 7.5-in "2BY" rear ring gear belongs in hi-altitude Buick diesel 4.3 liter engines. The vehicle has 218,000 + miles on it via NC State DOT registration records. Torque converter locks in at 34 mph. I'm real light on the accelerator and I plan way ahead in traffic. The car holds 65 mph real well and doesn't take much input to keep it there. I had the '79 267 ci V-8 2 BBL, ( 19-21 mpg), '84 305 4 BBL (17.5 mpg) and a creampuff '87 305 4BBL with the 4AOD automatic (21-22 mpg). Most of my driving has been interstate but I don't know any specs on anything but the '83.

So far the '83 is the surprise in more ways than one.