I've only had one I6 truck and it wasn't long because of how big of a turd it was... With that said I'm wondering what makes the better and more efficient truck motor with some reasonable mods. That includes mild head porting and head swaps.

I've got a few 86's and love the Bullnose trucks so at some point I'd like an 86 Bronco. Well I'd settle for an 83-86, but you get the idea. I'm thinking manual trans and mild tires, probably 31's but maybe 33's. Gears TBD. I'm wondering what would give me the better mileage and make the better DD. I'm not afraid of an EFI swap and would likely use MegaSquirt to get better control over fuel/spark. My 89, which has been sitting and has title issues, got 10-11mpg pretty much everywhere I drove it. I was a bit heavy footed though and my 86 F150, also an EFI 302/AOD combo gets 14 or so and I've seen 20+ on a long country trip mostly at 50mph on flat roads with few stop signs. The Bronco is heavier though.

So carb vs EFI, 300 vs 302... Real world info is the best, but some armchair mechanic stuff is cool too. I'm thinking the 302 would do better with more gear, even MPG wise. All the 302's I've had loved to cruise on the highway at around 2,000 RPM. I'm probably going to look at a 5spd, but an AOD wouldn't be out of the question as long as I can hook up the TV cable. Did Ford ever offer the AOD behind the 300? All I can ever remember seeing was the C6 or the E4OD.

I was talking to my cousin the other day while I was helping him with my tow truck. He used to run one for a gas station he worked with and commented how the 460 I had would move anything. The station he worked at had a 351w truck and one with a 300 and he said the 300 towed just as good as the 351w. The 351w truck was an 89 and the 300 was before that, so it was probably a carb'd truck. Neither was fast but both pulled anything you hooked up to. So it got me thinking...

 

The 300 and the 302 are pretty much the same cubes. You are correct, the 302 "loves" 2000 rpm. The advantage the 300 has, it will "love" 1500rpm. That's where it has a advantage over the 302 as far as fuel mileage. The 300 gets the same cubes with two less cylinders because it has a longer stroke. It will seem like it's very lazy, not gaining rpms like the 302, but like was mentioned to you by your friend, it will pull a load better than the 302 if they are geared the same.

It sounds like you want a compromise and fuel mileage is not your top concern, because running those oversize tires is a big no-no for fuel mileage.

 

A good rule of thumb to get the best mileage from any engine is to gear it so it's running about at (or slightly under) the torque peak at the cruise speed where you want to maximize your mileage. That's why the 300 loves lower rpms than the 302.

 

here is some food for thought...

my 96 302 5 speed Bronco with 4.56 gears and 35" tires get a Consistent 15mpg
And hauls the mail to boot

I would like to see a 4.9 do that

 

Done.

My 85 307 (300 bored .05 over has 390 pistons 10:1cr high ratio rollers and an rv cam) with a zf5 3.55 gears and 36" tires gets 14 and I haven't tuned it yet.

Plus I'd like better gears. 70mph in 4th is 2k and 1200 in 5th.

And it spins these tires at half throttle under 2k(i haven't taken it above 2k yet and I haven't meant to spin them yet )

 

So cubes and HP requirements basically mean they get similar MPG. I was wondering if that was the case.

I'm not thinking absolute economy at any cost, but it's up there on the list. These trucks look dumb IMO with 235/75-15's, so I would trade a little for a good look. I don't think 31's are a bad compromise. Actually I think all my trucks run basically a 31" tire or bigger now.

The more I think about this the more I realize how I'm getting a little tired of my 04 Ram with it's 4.7L engine. It's a runner for sure, but you've got to wind it up for it to run. I've moved and there are more hills and lots of hills that I can lug my 460 tow truck up that my 4.7 is kicking down and revving at 3,500+. In a drag race the 4.7 will blow the 460 away, but the 460 doesn't care what gear it's in or what hill you hit. The 351 in my F250 does a better job maintaining speed going up hills at a lower RPM than the 4.7, but again, slower in all out acceleration. But hey, these are trucks, not race cars right?

Now I'm thinking of selling the Dodge and getting another Ford to be my work truck...