Well, after hearing how there are several members here getting upwards of 26-28 mpg with their lower geared cars, I'm seriously considering swapping out the 3.73 gears in my daily driver 84 Trans AM for 3.23 or (GASP) 3.08 gears. What do you all think of this idea? Summit sells them for $145...Do you think I'll save enough in gas ($3.40 a gallon here) to offset the price of the gears? I'm hoping to improve on the 22mpg highway that I"m getting now with my stock 305. If I can get just 3 more mpg that ups me by 36 miles to the tank...if I can get 4 that's another 56 miles per tank ...any thoughts?

Nobody wants those 2.73 gears. Should be able to get those for real cheap.

Anything below 3.23, and you'll have to change the carrier too.

No I don't think you'll even get 3 mpg. Maybe none at all, might even make it worse. Instead, I'd suggest concentrating on cheaper things that WILL DEFINITELY make a difference, and don't cost much; synthetic fluids in engine tans and rear, tires at their FULL RATED pressure, good front end alignment, good air filter with low-restriction cold air induction, new spark plugs, clean & repack wheel bearings, and so forth.

I've already done most of that. Even with my new headers, new spark plugs, new distributer and wires, new air filter, checked and set the timing, got the right tire pressure. I managed 22.2 miles over a 300 mile road trip. I got 308miles out of my tank which measured out to exactly 22mpg. When I filled up, I put 14.2 gallons in (So much for my theory of having a 14 gallong tank...) but then again, I did make it almost overflow when I filled it.

I was just looking at options due to the really, really expensive gas out there.

im seriously considering buying a little POS toyota/honda for the summer cause my silverado ss is a gas hog.

No kidding... when I was stationed in Hawaii gas prices were up to $3.54... and when I left they were getting higher. Since I drove my third gen cross country I swapped some cheesy 2.73 gears in, and out of my HSR 406 / 6 Speed I was able to get 23 MPG. Not that bad considering I just have a 13 gallon tank. It was definately a fun drive though....

The same as with drag racing, remove weight. Take out everything you don't need, the less weight the engine has to move the less work it has to do and the better mileage it will get.

My daily driver is a 91 454SS. Putting gas in it is still cheaper than buying a new truck and I need a truck. For $40,000+ I can buy a lot of gas. As long as my truck stays reliable, I'll keep putting gas in it.

It's about as light as I can make it. I don't carry anything in the back an the only things in the trunk (what passes for a trunk anyway) are my jumper cables, road mechanics kit (one of those 53 pieces kits) and my spare tire (got an S10 spare that fit real well in the stock location).

I have always thought that if I can make the engine run less RPM's at a given speed I should be able to get a bit more mileage out of it right? Maybe it's just wishful thinking. Problem is, I can't even go put 10 bucks in anymore and get a quarter of a tank. That sucks so bad! Another reason I was considering it was because I drive 15 miles to work one way each day and it's mostly open highway (the base is about 15 miles from town). I guess I could sell my house and try and move on base...but that's a bit drastic don't you think?

My '83 Z28 has 3.23 rear gears with a 700r4 and she averages 22 mpg on the highway(this at sea level).She's a stock LU5 except for ignition and K&N filters.I did add a single HO snorkel inlet for cool air when the air doors are closed..With 3.73 gears,at altitude,you're doing very good to be getting 22 mpg on the highway.I'm not sure how much you would improve going to 3.23 but it may be worth the try.

the problem with changing gears, you may take the engine out of its powerband, and if you lose enough rpm at the same highway speed, its going to take more throttle to maintain your speed.

If its EFI, Get into chip burning and optimize the setup you have.
Some leaning out on the highway and keeping the converter locked during decelleration can give you some MPG.
If it is a carb setup there are some tweaks you can do to get a bit leaner too.
Just another option.

Well everyone I am sure would like to know how much if any difference in MPG you get when changing gears so go ahead and do them...then let us know about the MPG. Thanks and good luck.

-Gas here is $3.50 everywhere...thats for the 87.

P.S. My work is only a small walk away, so saving gas is easier in my case. That and all my friends live 1 or 2 streets away...another gas saver.

Well, I had a 400 with a big roller cam etc; got 18 mpg on the highway with the stock gears. Tore them up, dropped to 3.23. Got 17 mpg. Finally got sick of the highway setup and put a set of 3.73s in it to make it back stock, went back up to 18.

With a 305 in it and the stock T-5 and gears (.73 OD & 3.73), it got about 22 mpg. Put a T-56 in it (.50 OD & 3.73), now it gets about 24.

YMMV (or maybe not)

Well, my car came with 3.73 gears and a 700R4. I get 21mpg at 75. I backed down to 60 on the same trip, it took me nearly an hour longer but...and Il got 22mpg with my current gearing. So going slower really didn't help any. It's an 84 T/A which is carbureted. It's the only year Pontiac didn't offer a TBI or TPI option.

The way your testing is going you mine as well buy a honda or something...I dont think anything will change it enough for ya. IDK Keep us updated.

Isnt 20+mpg a good thing...my buddies 02 4.6 Police Interceptor gets 13-mpg.....he then put in injector cleaner and gets around 15-mpg now, and he likes that...says its a good thing, so I am reading this with 20+mpg and kind of wondering where bad mpg is? Anyway good luck and hope you find out what helps you into the 25mpg range.

If I buy another car my wife is going to throttle me with my own spark plug wires! I'm just looking into other options that aren't as drastic as a new car...especially since the gas prices are going up and don't show any signs of slowing down. Yes, for a 1984 car, 20mpg is good, but remember, when this car came out, gas was like 50 cents a gallon. Now it's 6 1/2 times that.

True True...around here they say by Summer (when school lets out and yes I already graduated) that prices will peak near $4 easy. Right now its at $3.49

It's $3.39 here in Clovis, NM. If I cross the line to Farwell, Texas it jumps to $3.49. It'll be at $4.00 here by July 4th I'm sure.

I dont even wanna know how Cali is feeling....they had around $3.50+ when it was $2.30- around here. Anyone from Cali have reports of their gas prices.

Check This Out:

Posted May 23rd, 2007

UCAN News


Today, the pain at the pump in San Diego was eased ever so slightly by a decrease of 5¢ per gallon on average for regular unleaded gasoline.

According to UCAN's Cheap Gas Locator survey, the average price of gasoline in the county is now $3.41 a gallon, down from 3.459 last Wednesday. Gas prices reached an all-time inflation adjusted high of $3.50 on Tuesday May 8th and have been declining slowly since then.

Meanwhile, gas prices are increasing nationally. According to the Department of Energy Energy Information Agency's Gasoline and Diesel Fuel Update, national gas prices have reached an all-time record high of $3.21 a gallon, up 35¢ from last year. These price declines are happening against a tidal wave of mainstream media stories that gas prices are increasing nationally and in California due to increased demand by consumers who do not care about the price of gasoline.

Don't you believe it.


Are Americans really using more gas? Probably not.

According to the mainstream media, high gas prices have had virtually no effect on consumer buying. A steady drumbeat of stories from the Associated Press, USA TODAY, and a host of network TV news shows have asserted that Americans are guzzling more gas than ever and that the high prices have not affected consumer buying habits. But recently, many analysts have begun to rethink this assumption.

Three months ago, UCAN asserted that gasoline demand was down in California, and documents from the California Board of Equalization concur. On April 13, the Board of Equalization reported, that gasoline consumption for the last three quarters of 2006 was 112 million gallons less than the comparable period in 2005. This was the first decline in the state's gas consumption in 14 years. The average statewide gas price during the nine months was $2.958. The board said Californians may be avoiding long trips or switching to fuel-efficient vehicles such as hybrid cars. With gas prices averaging nearly 50¢ a gallon more this year, it is highly unlikely that consumption has increased.

On Monday, OPIS, the Oil Price Information Service, reported in its newsletter (Vol 27, No 21) that media and government claims of increased fuel consumption in the USA should not be believed. "Talk to western chain marketers and they will confirm that sales are flattening ..."

What's more, consumption figures from the federal Energy Information Agency (EIA), and the federal Department of Transportation (DOT) do not jibe. According to CBS News, the EIA says consumption is up by 2%, while the DOT says Americans are driving 1% less.


What's happening?

UCAN believes that even though there are more drivers on the road, consumers are probably buying significantly less gasoline. It will take awhile for the statisticians to catch up. Reduced demand is finally forcing prices lower. But "lest there be a misunderstanding," San Diego and California are long overdue for lower prices. If the market was truly competivie, our gasoline prices would be significantly lower than what they are right now.

Well considering we use the imperial gallon up here. Doing the conversion to the usa gallon. We are paying 4.985 cents a usa gallon up here and I have seen it up to 6.00 a usa gallon 2 summers ago. I just went accross the line today to pick up some parts and it was 3.14 in Houlton Maine. I have 2 gas tanks on my old ford and I filled them right to the top. Pays for my trip . I can't wait to get my TA out in a few weeks. I don't let the gas prices bother me too much, I have never actually looked to see what my TA gets and I have had it for 17 years.

The rate of 4.985 and 6.00 is in canadian funds

Yeah I dont really care much either....just would be nice if it were lower...would mean more money for oil changes, detailing kits, etc etc. Ah well....cant wait to see the diff. in the rear end gears and their MPG.

Ya I would be probaly more concerned if I had to drive it on a daily basis . I am glad the wife has her 4 cylinder. I run my car on the weekend for a family trip into town and during the week now and again for when I need to get away and relax .

Keep the gears you have and install taller tires. Typical stock car tires are 26" tall. There's enough room for a 28" tall tire. That will be like putting highway gears back into the diff.

My truck has 4.10 gears, 28" tall tires and a 4L80E tranny. The 454 BBC gets 11-12 mpg in the city but also weighs 4600 pounds.

I've got an '84 T/A with a 120,000 mile clapped out 305, 700R4 and 2.92 gears. Everything is stock (except the gears) and I just rebuilt the carb so it is running really good. I'm getting equal to about 26 or 27 US mpg on the highway since the carb rebuild. I think what is doing it for me is I've given up pretending it's a race car. No hard pull aways, no fast cornering and never above 60 on the highway. The car is just for cruising on nice days now. Take out the t-roofs and enjoy the sunshine. I do very little city driving, mostly back roads for the scenery. Better mileage can be done, but changing the rearend and not changing your driving habits ain't gonna do it.

Premium out here in SoCal ranges from about $3.50 to $3.75.

But this isn't a 'gas crunch,' as you call it. This is how it will always be. So whatever changes you make, you better be planning on keeping your car that way forever.

This is it now. It's not going to get cheaper ever again. Sure it'll fluctuate here-and-there, but it won't change much.

I posted something similar last year, too, when people were in an uproar over the approaching $3 mark, many believing it was just a passing thing. And here we are a year later approaching $4.

Seriously, if the price of gas affects people that much, then they need to be driving different cars... cars that get 35+ mpg.

Well, right now my T/A is my daily driver so it hurts. I can go about 8 days of driving to work and back before I need to fill up. If I have to do any errands, that drops to about 6 days. It hits me hard right in the wallet. You can placea a pretty safe bet this family will be looking into one of those 35+mpg cars in the next year or so. The downside is, I'll probably cost me either my 84 T/A or my 67 Camaro. No way my wife would let me keep two garage queens.

Right now I'm running 215/65R15's. Stock Wheels and tire size. What size would I need to go up to in order to get that extra 2"? Take a look at my cardomain if you need to and let me know. I have been looking at a set of 16 inch wheels but we can't afford that right now. Besides, I'm under orders to save up so I can fix the leak in my engine! (Does happy dance at the thought of a new motor!!)

Yes, the higher gear ratio should help some, especially if the motor has good low end torque. Yes, gas consumption has gone down in California, due to about 275,000 people moving from the state last year, this is mainly due to "white flight". The illegals can't afford gas, and they ride how many in a vehicle?, who knows!!! When gas prices go up, it affects all business in a negative way. Notice the gas company monopoly is always in lockstep when it comes to prices. Remember when monopolies were outlawed in the early 1900's? and it stayed that way for years. Now there (the monopolies) are back and stronger than ever before because of lobbying (legalized bribery). I remember gas price wars (lowering prices to get your business, sound familiar?, and they not you, put the gasoline in your vehicle) this was in the 1960's & early 1970's till the small gas companies were eliminated, and now I could go on, but what the.......