I have a 94 f250 with a 351w that ive built into a decent mud truck ... From solid front axle swap, 6" lift, 39.5 swampers, f350 double cardon drive shaft, all new transfer case, and all kinds of things its a good truck, goes great in deep mud, haven't gotten stuck yet lol ... its just lacking 2 things. POWER AND TORQUE !!! it turns the tires fine but it does take a long time to get up to speed due to lack of power ... Mind you this truck is ALSO my daily driver ... Im stuck between a few ideas for this truck, its got a 351w in it, should i build that engine up, or should i get a 460 and do a nice budget build on it. I plan on buying a 78 or 79 and making a monster of it strictly just for mudding, should i wait to do a 460 build for that truck? If i built the 351w what should i do to the engine to make it a nice mud engine with plenty of horsepower and good torque for a small budget? If i just went ahead and built a 460 what should i do on that engine for power and torque. ..... Any suggestions, advice and tips are appreciated, i love getting feedback from you guys it helps me learn alot at 17... THANKS

 

What gears are you running? Kick it up to 4.10s. you'll lose some top speed but it'll get moving quicker and climb easier.

 

What trans does the truck have now? If it is the E4OD you will be limited with what you can do on a budget since the PCM controls both engine and trans so you can't rip off the EFI and install a carb for example.. the trans won't work right if you do. If the truck already has a manual then strip it down to the are longblock, install an aftermarket cam, heads, and 4bbl intake and carb and enjoy about double the stock horsepower. The axles will still need something like 4.56 gears though and a full exhaust system with headers.

 

There's no substitute for cubic inches...

 

I am running 4.10 gears

 

It is a 5 speed standard

 

well, with 39" swampers, i wouldn't expect it to be terribly fast. Sounds like a solid build and about what I would expect from what you've got. you could consider a fresh cam so it can apply that power differently and kick it up to 4.56s as previously stated. but to be honest, you're not in a vehicle designed to be a go fast machine.

Personally, i'd skip the gas 460 and go to a turbo diesel.

 

I considered do a 7.3 swap but theres alot of different things that go into that and im not much of a diesel mechanic, I have a strong erge to just get a 460 put it on an engine stand and start building a monster lol ... Then some day when its done id like to put it in a mega truck or a 48-52 f100 rat ... But right now im just gonna finish up this build and go from there i guess.

 

4.10 gears and 39.5" tires give the same final drive as the stock 31.7" tires with 3.29 gears. NOT a good setup for acceleration! 4.56 gears would be the equivalent to 3.65:1 with stock tires. Still more of an economy setup than for power. You need to get up to 5.11:0 with your tires to be the equivalent of 4.10s with stock tires. I'm not sure what ratios are available in that range. Maybe 5.38s? That wouldn't be an ideal daily driver ratio, even with your tires. But face it, anything with 39.5" tires isn't an ideal daily driver! Bottom line on this for me is don't waste your money swapping in 4.56 gears. It's not enough difference to be worth it. If you want the truck to work like it should you need to take a pretty big swing at it.

As far as which engine, 351, 460 or 7.3, a turbo diesel would be my last choice for your application. Turbo lag would be too annoying (although it probably could be addressed in a build) and the weight isn't your friend either. You ought to be able to get what you want out of a 351, but it might be cheaper, easier (and heavier) getting it from a 460. For what it's worth, a friend of mine just dyno'd the 340 he built for his '70 'Cuda: 400 hp and 500 lb-ft of torque! That's normally aspirated and on pump gas. It is bored and stroked, so it's about 412 cubic inches if I remember. And I think he said the engine build ran him about $8000. So big power from a small block is possible.

 

Mud takes TORQUE and plenty of it. You'll also want a decent RPM range since as you know that's how to keep the treads clear.

I'd at least stroke n bore that 351. Are you building this as a toy or for competition? If it's anything serious I'd go for a 460 and still I'd stroke it and punch it out to the max. More cubes is never a bad thing! Do some heads/cam/intake/headers/the usual and you'll have a badass muddin motor.

I have no opinion on diesels for mudding. Never owned one or rode in one that was actually mudding. Plenty of torque for sure though.

 

Yea my whole thought on diesel was the amount of torque easily producible.

 

I got a ride in a F250 4 door. A 2000 model with the 7.3 a few days ago.
First time in anything like that for me. I am here to tell you that this truck
would blow the doors off any 460 I have ever seen. I have been mudding
most of my adult life and have never seen anything with that much power.
Mind you it was not a stock engine as he said it was chipped and aftermarket
turbo and some other goodies. But it had 230K on the clock and ran like a
scalded freaking dog. This is an awesome engine my friend and well worth
considering for both a mud truck and a daily. That's my story and I am
sticking to it. I was impressed to say the least.

 

Agreed but expensive and more complicated to work on. My dad has a real nice ::gasp:: GMC with the 6.0 gas engine. Very nice

 

A commonly held belief about a lot of aspects of truck use, and while there's truth in it, it's not necessarily correct, and understanding where the truth is in it helps make better decisions.

First of all, technically torque doesn't do any work. All it does is lean against something. Once that something starts to move the torque becomes power. So horsepower is ALWAYS the ONLY important thing.

The truth in the holy grail of torque is that there are two ways to make more hosepower: make the same torque at higher speed, or make more torque at the same speed. If you go the "more speed" route you end up with a "peaky" power curve and it'll work great where it peaks, but you'll need to get the engine going fast before it'll do anything. Conversely, if you make more torque down low, then you end up with a flatter power curve and your power won't drop off quickly as you get away from the peak. So yes, engines with more torque are usually more forgiving (which is important in mud or pulling trailers up hills). But it's because the flat power curve lets you make good power more easily.

And yes, cubic inches, ESPECIALLY through longer strokes, are where you get the torque. So Dixie is absolutely right that boring and stroking a small block is a great idea for a mudder. Like my friend's 412 cubic inch 340.