Are you mostly interested in around-town driving? I would think about changing rearend ratios (if you can find one in a junkyard cheap), and then just tune, tune, tune. Cutting out some weight would also be a freebie.

Or highway driving? Then MPH is a freebie (slow down), and working on the aerodynamics would help. And maybe an overdrive, but I doubt you can do that for $100.

-BC

Shoot. I would look around for another cam, and try grounding off a couple lobes for a 6cyl. If that works, try to take a couple more off for a four. It won't be as good as an actual swap, but there should be a noticable increase in mileage if it works, and it's cheaper'n crap to do.

Besides the stuff already mentioned (air is free), swapping the lube for synthetics. If they're interested in hypermiling, throw in a tach and vacuum gage, preferably on the inside so it doesn't impact airflow, and use a low viscosity engine oil.

As far as driveline mods are concerned, I'd look for a tall rear end, like 2.29 or so, if you have what it takes to swap it out. My `78 Malibu had one and would spin at 2000 RPM at 60 MPH, even though it just had a 3-sp AT with no lockup. If you get one from the boneyard and labor is free, it'd probably be cheaper than new tires.

If you do need new tires, get the narrowest and largest diameter that will fit and meet the rim specs and safety inspection requirements; large diameter tires will raise the final drive ratio, and narrow tires will be more aero. If you have a mix of tire sizes, put the large diameter ones in back.

Major surgery?

Isn't Ryland helping 'em? He seems to have more than enough mechanical inclination.

My $0.02
 

Having had a few cars of almost this exact vintage and style...

-- Air up the tires (free!) :thumbup:

-- if the tires are not all that good, get some good LRR style used tires ($50 total) put on the beast

-- check alignment ($20 if you know the right mechanic if not free!)

-- new air filter (if needed, $5 to $10)

-- stay under 35/45 mph if possible to avoid needing any aero mods (biggie and free) :thumbup: :thumbup: :thumbup:

-- pull the plug on the a/c clutch in the summer (if it even still works, free)

-- consider disabling the secondary jets on the 4bbl carb...it will be a bit slower, but then if someone get a bit throttle happy, it won't matter as much. (free) :thumbup: :thumbup:

-- definitely advance the timing as much as it will tolerate w/o pinging (free) :thumbup:

-- check for brake drag & repack the front bearings

----- Get a good vacuum economy gauge and mount it on the dash ($50?)

Otherwise, if it is being driving so little, but hauling so much, it is doing EXACTLY what it was designed to do...and with a little bit of patient driving, it might get up to around 15mpg...but don't count on much more...12 isn't too bad for a 25 year old tank around town! :)

Now...if they can plan their driving, and make it a fun contest...they might hit 20mpg. It can be done, but realistically, with several college age drivers...15 is a really good goal...and at $3/gallon for 50 miles a week...$10 to haul stuff and people isn't too bad...just a pizza or two! ;)

My thoughts...keep it, drive it when needed, otherwise, get a couple mopeds, bicycles, hop on the bus, or walk...all good college activities! ;) :thumbup:

ok do a general tune up of everything:
NEw spark plug wires
(u already did plugs or thinkign about it)
new pcv valve
do a coolant flush and refil with new coolant
new belt(s)
do a tranny flush
change the rearend fluid
run a can of seafoam thru it.
repalce all vacum lines
clean all grounds with a wire brush in a drill
and what rvan said

Maybe a can or two of SeaFoam...to possibly free up any stuck vavles/rings/ect.

The only public transit we have is the Drunk Bus (I think it's still $4, and they will pick you up at your house), they only live 5 blocks from school, 15 blocks from work, and have a decent new bicycle that they plan to use thru the winter, and everyone has been warning them about the danger of rear wheel drive vehicles on snow covered roads.
I'm still waiting for it to get back from my friends dad who is doing an oil change and fixing a few things befor winter, and I assume that they would also be doing a tune up on it with new filters and spark plugs, but I know how much is really being done, so once it's back I figure I'll check things over as well, check the timeing, PCV valve, filters, rear end gear lube, sea foam it, pull the A/C belt if I can, I'm just not used to amarican cars, so I thought I would ask for tips.

Does the car have a block heater? Maybe try reduce the weight of the car.

Or SeaFoam, valve ajdustment, alignement, maybe all thats is doing ok... ?