Help me make the 300 better or should I swap for a a 302?

I am weighing the options and cost.. for the 1986 F250 4x4.

Either figure out how to make the stock 300 a better engine?  And what that would cost?
OR
Take 302 out of my '72 bronco with carb and drop in the F250.  Then I get new motor for the bronco, but that could be expensive.

How can I get the 300 to get better MPG, better power output, just better?

brian

All my opinion of course.


It depends on what you want really, as the 300 and 302 are different engines and do not act the same as each other.

The 300 has low end torque, and the 302 has high end.

My 300 gets most of it's power around 1800 to 2100 RPM. The 302 would not even be going good at those RPMs.

I've seen people try to overwind the 300, thinking it will produce more, but then the engine falls flat and wastes gas. This is because the engine is out of it's sweet spot.

Some questions . . .

Is there a mechanical problem with your 300?

What do you want to do with your truck? A 300 is a good motor for pulling, hauling, but not to win any races doing it.  The 302 is good for a family hauler, but not that great for hauling a lot of weight in my experience.

If I was to trade out the 300 for a V8 I'd consider the 351W.  

Amen, brother!  

The "It depends on what you really want" statement is the place to start.  Or maybe what you want to do with the truck.  Ford didn't put the 302 in the heavier-duty trucks for a reason, but it did put the 300 in them.  And it certainly put the 351W in them.  And it all gets down to torque and at what RPM.

There's another way to look at this - money.  You can build a 300 to spin faster than stock, but the stock intake and exhaust manifolds are very restrictive so have to go.  And now you are into different if not multiple carbs and the fun associated with that.

And you can get more torque than stock out of a 302 by going with a stroker kit, but that's big bucks.

On the other hand, you can get more torque at low RPM out of a 351W for less money than doing so with a 302.

But if you want an engine for just driving around in a light truck and maybe towing a light trailer once in a while the 302 will do that just fine.

BTW - it is a 4 speed manual.  The 300 has to get a running start at any hill.  And it feels like it is sucking the tank dry on every uphill.  We live on a mountain, we climb about 1500 feet with multiple 10-12 percent grades... this really pushes the truck hard and often heats up quickly.  It is 2nd gear all the way up, about 12 minutes to get up.

I know it is not going to win any 1/4 mile races, which is great as a 17 year old is driving it.

I am trying to make the truck just be able to respond to the throttle and not feel like we actually decrease speed when going uphill.

Will gearing matter?  See pic to help decode the tag on rear axle.

It is a matter of better intake, exhaust and carb?

As someone who daily's a 300 (and also has/is driven/ing it all over the continent) and has had similar performance issues, I'll give my $0.02:

-If the engine is tired (really bad compression, a ton of blow-by, etc) or isn't running right (carb issues, poorly done de-smogs, junky undersized aftermarket exhaust, etc.), all bets are off. If the engine hits a torquey situation, it's going to cough and misfire, rather than just hunker down. And to be honest, I suspect this may be the issue. It was my issue initially, and it took a rebuild along with a rehab of the carb, EEC-IV, ignition, and exhaust system before it was running "well"; there were many issues (to include every one listed above) holding it back. Still is a slog to drive in some cases (see below), but way, way better than when I first bought it. Terrible question: is your air filter soaking with oil? That was the dead givaway to the mechanical issue I had (poor compression due to broken rings causing a ton of blow-by).

-There's no good consensus on where the power/torque band is. I've had people swear it's 1700RPM. I've read 2000 RPM. And in my personal experience (especially the trip I'm on right now), it is 2000RPM. And anything under 1500RPM is very weak... inbetween is meh.

-My truck has 3.08 gears and an AOD transmission. For keeping RPM low, it's great. But, due to the above issue, it likes either 55-60MPH whrere one will be dowshifting on every incline pretty much, or 70-80MPH where it's running at 2000RPM in OD, only needs to downshift to 3000RPM on real hills once enough momentum is burnt off to put it 60-70MPH no-man's land (which is like 55-60MPH, but with somewhat worse fuel economy). And if you have a headwind, expect a lot more downshifting as if going uphill. Cruise only works without manual shifting/on flat land without a headwind (or heavy crosswind).

-The above point said, you have a 4spd, so no overdrive. In theory the 300 when running well should do fine here if shifted correctly with any gearing (lower gears better for offroading and towing)...

I'm starting the build on my 300 now, so I am/was in the same situation you're in.  I want to see what I can do with the big six, but if I was to change (and might if the 300 doesn't pan out), it would be to a 351W.  I love the 302, and 302-based strokers, but in my near-worthless opinion - they are better engines in cars than trucks.  In the early Broncos they were fine (though 351W swaps are common), but in the full-size trucks I'd opt for the W over the 302.  I'm going to stay with the six, since I originally started out looking for one.  And yes - I would guess gearing is going to be a major factor.  Mine is also 3.08, and will be 3.50 when I'm done with it, with also swapping the OD 4 speed for a T18.  I figure mileage might suffer, but I'm going to be using it as a utility vehicle, not a daily.  

For example with my truck. This is how it behaves

Pulling a 8% grade at 55mph is around 1800RPM and it will hold it's speed fine. If I downshift to third because of a slower driver, or turns etc, my truck will slow down to around 1800rpm, and stay there. If I rev the engine more than that, to try to speed back up, it just wastes gas.

So if I upshift on that same 8% grade to fourth, by revving the engine in 3rd just enough to drop the RPMs back in it's 1800rpm range, it will actually speed up more, than just revving it in third.

Exactly backward to my old and sold 1973 F-100 302V8. in my experience.

I would recommend looking at the Fordsix forums for a theoretical build and figuring out the most economical powerband and final drive ratio combination for you. Users there are doing all sorts of things. Drag racing, towing builds, turbos...

Powernation on Youtube has a few episodes showing where the horsepower gains are at. Stock carb, intake, and exhaust manifold are the main bottlenecks for a stock engine. You could upgrade all 3 for maybe $1200 and that's at least 40 horsepower right off the bat. EFI exhaust manifolds are just as good as anything aftermarket and they are cheap. Fuel injection is also a huge upgrade. You can surpass the horsepower (and bury the torque) of a stock 302 or even 351 with a mostly stock 300 bottom end and still get good fuel economy. With the things I see people doing with 300s, I think it's a good choice for an economy truck engine.