Guys, I've recently been handed a setback which I'm thinking might be one of the best things that's happened to me. My '74 highboy finally grenaded the FE360 which Averaged 4 MPG with a best of 6 and a worst of 2MPG it was old and tired.

The big question is this what if anything would I need to do to a 300 to put one into Frank, outside of the perches, mounts, and tranny. I have 411 gears in a Dana 70 rear, 44HD front, running 35's.

I'm not looking for freeway speeds, in fact despite having a turboed V8 grand Prix GPX as a daily driver I rarely see the speed limit ( I usually don't get to it, not once up and once down )

What I want is a truck that'll pull my sorry butt, a stock trailer w/ 6 head, and all my gear into and out of the mountains of Wyoming Idaho and Montana reliably. Total Gross on that load runs 15,000 not counting the truck and me. The 360 did it with out much complaint, although I got passed like a turtle at a race track on most hills.

Also is there a 4 or 5 speed OD tranny option to look for? Milage will have to be better than what I had, but I'd be tickled with even 10. My main reason for the switch is a love of simplicity, a hope for better economy and stubborn "death before replacement" desire to never give up on my truck.

I know that they were used in Tons of the F5-700's among other things, but what would YOU do to increase improve and bulletproof the motor before install?

Matt

 

A 300 pulling a stock trailer... Itd do it but it wouldnt like it lol. Dont forget, they only made 175 horsepower.

If I were you, Id step it up a bit and go with a 351W. Theyve proven themselves to be good runners, decent mpg, and will pull a trailer without a hiccup.

I love the 300, but its still a V6 lol

 

The 300 is not a V6, it's an inline 6. Big difference in terms of torque. It's ~175hp and ~215ish tq, so it's on par with a 351w (1992 EFI specs are 210hp/300ish tq) given it's two less cylinders and 51ci less in size. I have one in a '96 that's an absolute blast to drive. You can take off in THIRD gear with no issue, and it has 2.73 gears. Those 4.11 gears aren't helping you any, if you need good pulling power and mileage swap down to a 3.73 gear. Then bolt on 1.7 ratio rockers on a 300, use a 4bbl intake and spreadbore carb. EFI exhaust manifolds and a ZF 5spd with the 'small block' bellhousing. That will give you a decent LOW gear and if you need more you can always swap the TC into low range.

 

Back in the 1980s a very large ranch near me replaced their trailer-towing rigs. They had been running one ton Chevies with 454s. They replaced them with F-350s running 300s. Now this isn't mountain country by any means, but they pulled 40 foot goosenecks loaded with cattle 70 miles to the auction with them. The ranch manager told me that the Chevies out-ran the Fords to start, but the Fords could keep them in sight for the whole trip. Plus, the Chevies got 4 mpg, the Fords got over 10 on the round trip.

You may not get there fast, but a 300 will get you there.

 

If your truck currently has an FE you shouldn't need to swap out the perches. The FE's and 240/300 used the same perches.

I would go with an aftermarket intake, a 2V or 4V carb and a pair of EFI exhaust manifolds on the 300. That will help with the power and could also improve the mileage too.

And if you want an OD manual transmission and plan to tow the only real good choice is the ZF 5spd. It would take some fab work to swap it in. The ZF requires a hydraulic clutch master cylinder. I personally prefer the good old NP435 or T-18 grany low 4spd ( no OD ) . If you want to run an OD unit Advance Adapters makes an add on OD unit called the Ranger. It mounts between the bellhousing and transmission. So it moves the transmission back. Which means having your driveshaft between the transmission and transfer case shortened. I believe the AA Ranger OD box is like $1300.

 

Whoops lol. Was typing faster than my brain was workin.

Anywho, I believe the 300 will pull it, but dont pull out in front of anyne on the highway lol. And the addition of a granny low would help tremendously IMO

 

Yeah, perches are the same, just need to move them forward. I've done the swap on those trucks when all the frame bolt holes weren't there for the six banger but I just welded the perches down, 15,000 gross is asking a lot from the 300 in the mountains. I've grossed 16 with mine and end up in third on every kind of small long hill. Plus bucking a wind will take all the poop out of it. It will get along pretty good with 13,000 though, I can get in 5th on flat ground.
If you do the swap, get a ZF 5 speed and stay with the 4.10s, it will pull pretty good and you still have a final drive ratio around 3.23. You could even go 4.56s and still get by. With the 4 speed (which is really a 3 speed functionally) the 2-3 split is horrible for towing, you have to practically float the valves in 2nd to get it over the hump for 3rd. Actually from 3-4 too.
I have a 390 holley on an Offy C with efi manifolds and a homebrew HEI with duraspark dist, efi coil and GM module. It's a pretty good setup except I have a Comp 268H cam which moves the powerband up and frankly looses some of the low end grunt that is the charm of a 300. If I ever get around to it I will switch to a stock cam or Isky mile-a-more for better low end. And port the head.
I did a port job on my old 72 and it was well worth the time and effort. You don't have to be a porting guru to do it. Just clean up all the casting flash and take the valve guide bosses down. I did a gasket match too but I don't think it is all that crucial now, just take off the sharp edges.
Now the truthful part, the mileage is so horrible when you overwork that little engine that I truly believe a decent 460 would be a better way to go for the towing. It will pull more and use less gas doing it.

 

The 300 was rated at 175hp back in '65. After they changed horsepower ratings in '72, it was rerated at ~120hp.

Carb'd 300:

122hp @ 3000 RPMs
255tq @ 1400 RPMs

EFI 300

145hp @ 3400 RPMs
265tq @ 2000 RPMs

 

But the 300 cid had 300+ lbs of tq.......as much as the 351W

 

I agree with this statement. I recently hauled 6000 lbs worth of racecar with my 460 and it cruised like a champ! Best part? Averaged 10 mpg. Without the trailer? The same. I know thats only half but you get the point.

The numbers comin outta that 300 are similar to the Ranger I traded for my F250: 205 hp and 215 ft lbs. I towed a trailer a few times with a tractor on it (about 3000 lbs) and it hated every second of it. Itd kick down on smaller hills, with the OD off! And it had 3.73s! I couldnt imagine pulling 12,000 lbs...

 

Did you read the guys post ahead of you lol

 

willowbilly3: "...Comp 268H cam..." Yes, that cam I think is a bit above the "RV" range. I have a 260H and I'm entirely satisfied with the performance under load with it.

 

Yeah, the engine was kind of a gift from a friend and already built when I got it, I would never choose a 268H for my driving needs now that I've owned one. I had the 260 grind in my ported engine in the old 72 and loved it, but I didn't tow the kind of loads I have with this truck. I have got by with the 268, just had to learn to keep the rpms up a little more than what "feels" right
I have an 80 engine in the hold pattern and all the stuff to do the shortblock with the FE pistons. It will get a grunt cam and ported head, not sure on the induction but probably not a 4 barrel. (Unless maybe a small quadrajet.)

 

Hold on here, I think somethings being missed. RunninD's truck's got a 360 in it, a very wore out 360. If a wore out 360 moved 15,000 lbs gross, a fresh healthy 300 will have no problem. A brand new 360 wasn't exactly a powerhouse, especially not a smog era one. They're a great motor, but their known for their long lives, not their power.

The 300 won't do it as fast as a big v8, but it will do it. And I'll bet it would do it a lot faster than that 360.

Sam

 

I bet a 460 would do it all around better lol. Only difference would be the 300 would get better mileage without the trailer