Hey guys, my friend was selling a 1983 305 bird, so I decided to jump on it and I bought it for $800, I have yet to ride it (besides the test drives, drives really good) because its not insured yet and here in So cal, the car Nazis don't play, what I'm wondering is, how much of a difference is a 3.1 from a 5.0 when it comes to fuel economy, I have a 92 bird v6, I don't get rid of it because it has good MPG, if I sell it, will I regret it when it comes to MPGs? The gas prices are now $4.67 a gallon, what have you guys noticed from your 305, is the mileage ok or am I better off hanging on to that v6? Thanks guys.

Since this question is really aimed at V8 guys, I'm going to move this over there. Hopefully get you some good responses.
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Well, being an '83, it really doesn't belong here 100% either, but I know some of you guys will have an answer for this.

305 TBI, 700R4, B/W 3.27, avg. 17 - 20 mpg. Typically, the lower as not often hwy driven.

I have the 2.73 highway gears and just manage about 15 on the highway. Less than 12 city. Functioning torque lockup and fresh tune up even.

My car just sucks on gas.

my old worn out 305 got 25 mpg on highway but it was tbi, i seriously doubt your carburated will get anywhere close to your v6 fuel mileage. if thats what you are worried about i wouldnt get rid of the v6

My CC-carb 305 got 25 highway with the stock 2.73's.
Now gets 22 highway and 16-17 city with the 3.73's

My TPI 305 got 12 mpg the last time i had a full tank 156 miles on it. im thinking somethings wrong lol

My 86 TPI 305 auto 2.73 gears gets anywhere from 13-16 MPG all around city and highway

My 87 TPI 305 auto w/ cam and 3.23 gears gets about 14 mpg city and highway

I noticed on mine it really depends on the way I drive it. Most V-8's I've driven can get fairly decent gas milage (if I keep my foot out of it). But like most other cars, if you're racing it around everywhere, your gas milage is gonna go way down. Normal driving for me I get around 20-22 around town with my 305 TBI.

With my TBI 305, I have done 18-20 city, and up to 32 on the highway...

but that is the TBI motor. The older carb 305's are gas pigs.

Somewhere around 19-21 mpg when mostly city. Consistent highway 26 mpg, but that's cheap $3.84/ gallon gas.

Ive got a 305 with 145k miles, 2.73 gears but with a tpi and I average 19-20 mpg

my 350 tbi gets 22-24 on the highway...w/ 3.42 gears

3.84 where is gladstone located? Im at Fort Wood and its 3.99 for 87 Octane

3.99 I wish, here in Chicago $4.39 for 87 octane........ Im going to have to load up the mountain bike with tools and start taking it to jobsites.

oh I wasn't complaining after the 4.67 comment but my car only runs on 91+ so its up there with you guys, damn arabs!

Gladstone is a suburb of Kansas City, but the 3.84 is in Saint Joseph.

Thanks for the info guys, yeah I have two 305;s one 89 Iroc TBI and one 83 carbed, from what I'm hearing the carbed is going to be a killer with gas and the TBI is not going to be that bad, now I'm wondering if I should just sell them both and get a 2002 Camaro SS, since its easier to get accepted for a car loan because of the economy, but I don't know I'm thinkingn about it, do I want to pay monthly for it or just fix what I allready have? I also have a v6 which is going to become my brother's. What would you guys do. Reliability 2002 SS or little by little get the third gens a paint job and some engine work, THANKS for all your opinions.

My dad has an 86 IROC with the 305 engine 5 speed, computer controlled carb.

We put flattop pistons and the L69 cam and computer from an 88 Monte Carlo SS (L69 computer). If its in good tune, it gets about 20mpg all around.

Here in So Cal its $4.56 a gallon

16-22 in town depends on my foot hwy 24-28 i also have TBI along with the amazing ebl flash which paid for itself. EBL is my best friend

Bone stock 92 RS 305 TBI 18K miles 2.73 rear 700r4 anywhere between 25 - 28 with a mix of hiway city easy hard driving. Once this thing dumps into overdrive and locks up the converter it's barely idling.

my tbi gets about 18-20 city and anywhere from 25-30 highway but like everyone else said yours will probably be a little worse. i used to own a v6 firebird and i regret selling it because compared to the v8 with even the mileage im getting now the v6 was awesome on gas.btw it was a 1992 3.1 5 speed.so i would say defiantly keep the 3.1 it will be worth it.

All thirdgen 305's w/700R4 4 spd autos:

87 LG4 (carb) Best: 27 mpg. Consistent hwy avg: 25 mpg. 2.73 gears
88 TBI Best: 28 mpg. Consistent hwy avg: 25 mpg. 2.73 gears
89 LB9 (TPI) Best: 26 mpg. Consistent hwy avg: 24.5 mpg 2.73 gears
same car, 3.23 gears, Best :24 mpg Consistent hwy avg: 22-23

87 v6, w/T5 Best :29 mpg Consistent hwy avg: 27mpg. 3.73 gears,

What is EBL flash?

1991 305 TBI 5-speed 23 MPG

Same as my 2000 3.8 V6 Firebird....

If I were you, I'd just fix up what you've already got..

The best thing I ever did was buy my bird and fix it up to be my daily driver. I don't miss having monthly car payments one bit.

A couple years ago while on a 275 mi trip to Cincinnati, I got 28-30 mpg highway on cruise ctrl (70-75 mph) and keeping my foot out of it. I was also running mid-grade 89 octane fuel. At the time, the L03 was completely stock.

http://www.dynamicefi.com/

itd be hard for me to pass up a 2002 SS unless it was some ugly cvolor or black, but a white or red one is a major drool for me