How to add horsepower to a truck?

I have a 1994 Ford F-150
It has a 4.9 Inline 6 Engine
This engine is great for towing but I'd like to make it a mud toy but everyone says there's no making my engine stronger

80 yeas or so ago racers would add 2,4,6-trinitrophenol to their fuel. It produced tremendous amounts of power, but the engines usually lasted no more than 1000 hours, and often simply exploded. Highly not recommended. Highly explosive.

Other methods include adding a turbo or changing the cylinder head design. Expense and danger will be limiting factors.

Trading for a different engine or a different truck might be best, although I heard of one fellow who put a Lycoming aircraft engine into his old VW bug. The most engine in the least vehicle. Supposedly had awesome results.

It would be a lot easier to answer this if you gave us a budget to work with

I'd really like to keep it cheap but if it costs money I'm willing to do it

You can build that engine to get more power, but it'd be cheaper and easier to swap in a bigger used engine.

I don't agree. You just have to be realistic with what you expect. A straight six 300 is a good motor with good torque. They make intake and cam improvements for that engine. That and an upgraded exhaust will help. For mud though you either need horsepower or the right gearing. For a 300 motor it's going to require gearing.

Yes it is possible to build up the 6, but the common problem is that not too many people do that, so the parts are harder to find and more expensive than comparable V8 parts.

But then again, on a "Top 10 engines of all time" list it made #4, the most highly rated Ford motor, with Ford 351 Windsor V8 barely making the list at #9.

http://www.onallcylinders.com/2014/01/22/top-10-engines-time-4-ford-300-i6/

You can find manifold/carb/headers kit for about $1K at Jegs.

http://www.jegs.com/i/Offenhauser/750/6019-DPK/10002/-1

There isn't any way to make it stronger without having it fully built. But american engines are cheaper to swap out than build. So go put a big V8 in it instead of wasting your money on those useless "performance chips" you get off of ebay. Or those cold air intakes that are mounted right next to your hot engine that claim to add 100hp.

Good luck lol my dad had that same engine, yes there are a few performance parts out there that will bump the power a tad, headers and ECU tuning for example, but I wouldn't expect to get more than an extra 10hp without more than a few grand in upgrades. Honestly, if you want more power, it's probably far more cost effective to just sell it for whatever you can, and go get one with the 5.8 V8. Sure it may cost you a bit more than you probably hope to spend, but honestly, for the money difference, you're going to get far more used bang for your buck just switching to a V8 truck.

It's not "impossible" to get more power from that engine, but because it's not a commonly "hotted up" engine, you won't find many off the shelf parts. It's also a long stroke, hence slower revving engine, with good torque. (this is why it's good in a truck and for towing).

There may be some cheap tweaks you do (cam, manifolds etc) that might get you 10% more HP, but really that's barely enough to notice.

Going more serious will mean an engine rebuild and forced induction. Expensive as it will be custom work. You probably won't find a turbo manifold off the shelf, which means one has to be fabricated. Starts getting expensive.

At that point, it would just be more sensible to swap the engine for a mildly tuned 351 V8, which was a standard option for that truck. That takes you from ~145hp to more like 300, and would be cheaper and less work than trying to get that sort of power out of the Six. All the bits you need would be standard, from a donor vehicle. No tricky engineering needed.

Change the engine.
Go bigger!