I just got a 1986 Trans Am that's in fantastic body shape. Mechanically, it has a few problems which will be worked out. My gas gauge isn't working which I'm not real worried about for now. So I was wondering/trying to find roughly what the mileage is on a full tank - like 100 miles a tank etc. That way I can somewhat keep track for now. I believe it has the LG4 305 motor in it because it does have a carb. It is also automatic.

 

Tank holds 15.5 gallons. My carbed 350 gets 17mpg - if you use that as a rough estimate, that's say 255 miles per tank - as long as you refill every 200 miles just to be conservative, you should be safe. Throw a gas can in the trunk just to CYA!

 

Hey thanks a lot!

 

Your lucky my tuneported 350 only gets between 10-12 mpg and if Im lucky 15 mpg! It doesnt help that my engine is missing either! (and no I dont mean missing as in stolen)

 

a stolen missing motor would get great mileage!

Yeah, the TPI cars never got very decent mileage from what I understand. So much for computer-controlled emissions gas savings huh? Even today, a new VW beetle only gets maybe 28 highway? Back in 1966, a carbed beetle got better than 40mpg! Better mileage was and still is attainable without 1500 lbs. of batteries - they just don't want us to have it - they didn't then because of the oil, they don't now for the sake of funding "green" technology.

 

Im working on getting it fixed right after I figure out which cylinder is missing. After that (according to the origional build sheet) I should get 13-19 mpg city and 21-29 mpg highway. Or atleast I hope!

 

my 1991 5.7 TPI gets 16-18 in town, 18-22 on the highway depending on how i drive it. I currently have 3:73's in it, and I'm considering maybe going to a more highway-friendly gear ratio considering how much i commute about 1800 mi's/month, but then i don't want to lose the torque either lol.

 

My carbed 305 (Was L69 before the Engine swap), would get 15-19 in town and 20-25 on the highway with the cruise on at 60-65mph with a solid average of 22 at 70mph.