My 86 f160 has a 300 6 which has recently been condemned, still runs, but time is short. I have narrowed down to two options: another 300 or a 351 windsor. Everything is stock. The tranny is a four speed with the granny gear. My question is which one has the best power, towing, and mpg (please leave out the misconception that a bigger motor gets worse mileage, I'm getting the same as my dads f350 with a 460 and auto trans, though his is efi).

If I were to go to a 351w, what all would I need to change?

 

Well you will have to re do the engine mounts, the X member on the tranny may be diffrent, the exhaust will obviously be diffrent, the driveshaft will have to be diffrent because of the overall length of the engine (300ci is longer from timing cover to flywheel) check into that though i may be mistaken....all my engine swaps have been 4 cyl mustangs to 351W V-8's and i had to shorten and rebalance the driveshaft. The 300ci will have more low end torque than the V-8 BUT the V-8 will have more Hp and a more smooth hp/torque curve throughout the RPM's you will also get alot more "Grunt" off the line and at speeds when you kick it down a gear. The Winsdsor is a powerhouse and a great racing engine as well as towing and daily driving....i used my mustang to tow trailers that my buddy couldnt budge with his chevy truck for example....either way the 351W V-8 will give you alot of power and low end torque you wont miss the old 300ci except for the oil leaks...lol with the 86' you were carb, that means little to no computer stuff which is good....just carb a 351 and drop it in good luck man let us know what happens.

 

Actually the W makes more low end torque than the 300. It also revs higher, and has tons of performance parts.

Not to mention they are as cheap as 302s.

Your gas mileage should be around 15-17. Thats on a rebuild, if you opt for a junkyard motor (no rebuild or R&M bearings only), your guess is as good as mine.

Transmission, mounts, and radiator are the same and completely interchangeable, the motor towers are different.

 

well the specs on the 4.9L are 265 lb-torque at 2000 rpms and 145 hp at 3400 while the 5.8L is sitting pretty at 190hp@3800-210lb/ft@3800. these are FACTORY specs now no mods at all bare bone stock....

 

actually Matt i looked into it and the specs i gave were pre EFI where the W motor did soar out into the lead with a hefty 295 lb/ft....sorry for the mis-information

 

actually Matt i looked into it and the specs i gave were pre EFI where the W motor did soar out into the lead with a hefty 295 lb/ft....sorry for the mis-information


Well, My 300 is not fuel injected and the 351w I would get would be carborated also, so wouldnt the pre efi specs be the ones to use?

 

well according to the spec sheet i found it was pre 85 351w after that they changed some stuff to give it better grunt low end wise. Im sure you arent going to leave this engine stock are you>? when you slap on a 4 bbl carb and a nice intake with headers and maybe pull the pistons and give the cylinders a small shave then up the compression with new pistons and rods and slap it together youll be runnin like ya ate a box of ex-lax.

 

To put in a 351W, you're going to need a set of 302/351W mount towers, a V8 rad, and the engine, complete with brackets for the acessories(your alt. and PS pump will bolt to the new brackets) and the propwe flywheel/flexplate for the W.
Find yourself an 85-87 351W, they're the HO's(there was an 84 HO also, but, 85-up have better heads,) 215 HP/305 ft/lbs(86-87 spec, don't have 85 on hand,) 4bbl Holley, etc...
Throw some headers at it, and you'd have a nice power plant

 

OH YEA...they will fit on the crank but will NOT interchange from 302 to 351W they are something like .5 oz diff on the weights attached to the flywheel. Almost found that out the hard way when goin to a 5 speed from an auto and tried to use the 5.0 flywheel so make sure to listen to 82's advice there

 

hey 82 f100, you have an 82 f100 4 speed 4x4 with the 351w, what do you get for mileage, mine is a 4x4 and four speed, an 86 that i want to put the 351w in. And by v-8 rad, you mean a different radiator?
thanks

 

Looks like you guys covered most of the needs for the swap...if you can get a salvage motor that has the accessory brackets and all it will sure help. V-8 radiator would translate to a 3 or 4 core unit... Most 300's had a single core radiator... that wouldn't have nearly enough cooling capacity for the V-8. You should be able to find a radiator that matches the dimensions of yours and bolts right in, but it will be about 3-4 times thicker across the cooling fins.

If you find a 351W from the mid 80's there were many that came out as 351HO's... they already have a 4bbl intake and carb on them, and though it doesn't flow like an aftermarket intake would... they aren't bad really. The Windsor is a great motor, but the granny 4 would really be a bit much for it (IMO)... I had an 86 F150 2wd with the windsor and a C6 trans and it made a great truck, very quick, and sounds great rummbling through a set a flow masters. I prefer the 300 in my Bronco, the extra low end torque at such a low rpm is perfect for a rig that is a dedicated hunting truck... but for years it was my dedicated driver and has done well in both roles. I would say that for raw power, sound, and go fast the 351 is the way to go, if you can stand to be a little slower, you can get some pretty good mpg #'s out of the 300's with a little tuning. just my $0.02

 

I'm not really sure what mileage the 351W gets, I haven't burnt a tank of gas with it, and the engine isn't all that healthy(It was a $100 gamble... hadn't run in 4 years..)
For the Radiator, the V8 has the upper hose on the pass. side, lower on the drivers, opposite of the 300's configuration.
This engine isn't all that healthy, and is stock other than headers and dual exhaust, and I have about the same power my built 300 had, but, with a considerably more livable idle, and the power brakes even work right. Compared to the 300, it is lacking in low end grunt, and, I know it won't get the 18 MPG the 300 got(starving a well built engine with a 1bbl does that)

 

Hey thanks guys. I've only been getting 14 mpg with the 300 and thought I could get that with the 351w and have considerably more power. On the highway the poor 300 is working most of the time and I thought the 351w would do better there. sounds like keeping the 300 is the way to go, with all the extra changes. I would like the 351w, I need to work on being content with being the slowest guy on the road. As far as longevity, I understand the 300 to be known for very long life. So the bottom line for me is that I need to keep practical use as the focuss and stuff like speed/acceleration not affect my decision. The two practical things I was looking for were mpg, and extending highway usefulness. maybe just go with the 300 and play with a few things, and its the cheaper option.

Could you guys let me know what you think on strictly those two objectives?

Thanks
joseph

 

Try searching the Inline Six forums for performance options... You can get aftermarket intakes and headers for the 300's... different cams, msd ignitions, just like a V-8. I run a 2bbl motorcraft carb off a 302 on mine, it really didn't hurt the mpg that bad and I like what it did for the engine. There may not be as many options as you have with a V-8, but there is stuff out there for it. MPG #'s for the 300 are as varied as anything I've seen, a lot depends on gearing and such. I've had 3 with the 300's and they all get diff mpg's...

Bronco... stock had 2.73 gears and a 4 speed manual with O.D. With the 1bbl carb I got about 17-18 mpg average. 2bbl carb about the same. Now with 3.55 gears, I get about 14-16.

95 F-250... 300 EFI with 5 speed manual/OD and 3.73 gears... I get about 12-14

81 F100 stock 300, 1 bbl carb, granny 4 speed... not sure what rearend... I got 14-16.

But if you look where this question has been asked in the 300 forum your answers will vary for 22+mpg to 7mpg... All of my 300's were good motors... the 81 had 260K on it when it was wrecked (we had to shoot it to kill it) The 95 had 175K on it and still going, the Bronco has a new motor but the old one went about 150K and I lost it to an overheat. Very rugged engines.