ya i agree on the driving style changes, so go with the body work or the trans swap?

 

I bought a used 91 s10 4cyl stick for $1500. The difference between the 95 F150 & S10, gas money savings will pay off for itself in 18 months including insurance (break even this September).

 

Have you thought about buying a used CV?

With the 4.6 there are decent on gas and never give up. I've seen running ones go for about $1500 on occasion. It won't be a 03+ but the earlier ones are just as nice, and much cheaper.

 

My opinion, put a Y block in there. 302s just don't seem to be a good choice for these trucks if you're shooting for mileage. Without overdrive I get about 13.5mpg. With overdrive it's 16.3. This is with a 3.70 rear and 225/70-15 tires.

An overdrive transmission will absolutely be worthwhile, especially if it is a daily driver and you do a good bit of highway driving. If you spend $1000 on it, it will take about 85 fill ups from empty to pay for it, assuming that your results are similar to mine. That's only a few months to a couple years depending on how much you use it. An added benefit is that it makes it so much more fun to drive.

An electronic ignition, custom curved distributor and good carb will help a lot.

So, Y-Block, overdrive, good carb, custom timing curve, and electronic ignition and you should find 5 or 6 extra mpg.

A higher temperature thermostat may help and it's cheap enough to try. You want the intake charge to be cool but you want the cylinders and combustion chambers to be hot to provide the most complete burn. If your engine is not boiling over, it's not too hot, try a hotter thermostat.

 

if i hadnt just had the 302 completely rebuilt id be open to the y-block, im definitely leaning towards the OD. the 302 already has a holley 4bbl and ignitor ignition in it but i had forgotten about doing a electronic ignition.

 

A9: Spicer/Dana 60.2 rear axle / 3.54-1 / Limited Slip.

 

The more modern the carb, the better. I'm using a Street Avenger. If you are patient, the Demon carbs are reportedly excellent, but, here's where the patience comes in, you need to completely disassemble it and clean it when it is new out of the box, and you'll need to spend some time getting it tuned. And now you may need to exercise patience finding one. The people I know who have taken the time to do so say they will never use another carb. My experience with Edelbrock says to stay away from them if it's economy you're after. Plus they just have characteristics I don't like and in my opinion are not as easily tuned or simply as tunable as a Holley styled carburetor. They also are an old design.

The ignition does need to be something better than a Pertronix. I'm using a Duraspark based Performance Distributors ignition and I can tell you from experience that the ignitor 2 and flamethrower 2 coil are not even in the same ball park as the system I'm using. Pertronix is little league compared to this. It doesn't hide under the cap of the distributor so you do loose the stealth factor that Pertronix does provide and you will start to see more money in your wallet as a result.

Another thing to look at since an engine swap is out of the question is to increase the compression of the 302 to the maximum safe limit for high octane pump gas. You're going to say "but premium costs more." Correct, but the increase in economy and power will more than make up for it.

Long story short, to answer your original question, I really think it is a toss up. You will get your money back for the mileage increases if it is a daily driver, but it may take a while to recoup that money. Do whichever you think is more important right now.

 

good advice above......to elaborate....

many people think that getting an engine to run as cool as possible is best.....the truth is that internal combustion engines run most efficiently at hot temperatures.

It's a huge generalization, but what you generally want is to run as hot as possible without boiling over or endangering the engine's gaskets or materials.

The 240/300 sixes that I've had tend to run cool, which does not promote complete combustion of fuel.

 

And wear on the engine is decreased, which in the long run puts even more money in your pocket.

 

There is one catch to running hotter on a high compression engine, that is Detonation, aka pinging,dieseling, and the like. This can cause cylinder head failure, and burning of pistons. Just raising the octane is not the true answer. I have gone through a few heads with my drag boat trying to get max performance, with high compression, and high temp. Better to run a little cool, then to burn a hole between cylinders through the head, or have catastrophic cylinder failure. The mileage just isn't worth that headache.

 

True...that would fall under the category of too hot

 

There will have to be some compromise and fine tuning. If he's running 160 now, 180 will be better. If he's running 180 now, 195 might be better. Fortunately, on the street you have a little more time to figure things out. Pick an initial test drive route that keeps you close to home. If you hear pinging take it easy and head back home, or even shut it down, let it cool and then drive it back. I can tell you that high pump gas street compression works well with a 180 degree thermostat here in Atlanta. In stop and go traffic, It'll creep up to 200 and it does just fine.

 

im definitely gonna look in to the electronic ignintion, when i first bought the 302 i have right now the PO had been running electronic ignition but kept the computer so i went back with the ignitor ignition i had on the 289 before. the motor is running higher compression pistons and a mild cam but i dont know the details on either. right now i run pump gas and the engine runs right around 170 both around town and on the freeway.

 

Correct, but one warm day in LA traffic can make anyone run too hot! Better to err to the cool side in SO Cal! Which is where he lives. 10-15 degrees is just not worth the Headache to net 1/2 - 1 miles per gallon gained. If it ain't broke don't fix it! His truck is running 170 which is fine!

 

I drive my truck to work,(4 miles each way in country driving conditions-302) about 3 days a week. The rest of the time, I drive my 4 cyl. 4Runner.
Nothing that you do parts-wise or with "up-grades" is going to make any noticeable difference. It's a waste of money. Drive slower, and maybe drive
an economical car 1/2 the time...the 3 days a week I drive my truck gives me my fix. Sure, I'd love to load my longboards into the truck and hit
the coast for a nice surf session a few days a week, but it's not practical, and would be downright silly considering the price of fuel.