just bought my 92 F250 from some farm boys that used it for pullin horses. Supercab, 8' bed, auto, 190,000mi. Thought it had a blown head gasket due to coolant leak hard to find, slight white smokiness from tail pipe, running hot, lacked power. Take it to a mechanic and tells me he ran some pressure tests with the coolant system and its not the head gasket. he replaced the 5 out of 6 freeze plugs that were leaking, and that he thinks my injectors need cleaning since it runs a little rough at idle and theres a slight lag when you step on the gas.
Have not had the injectors cleaned yet besides additives. oh and previous owner removed the cat.

Beyond this i love this truck, but it feels like is lacking power some how, i expected the 351 in an unloaded truck to be able to get up and go, and climb moderate hills with ease, does it sound like theres a problem or was i mistaken?

Id love to upgrade the intake manifold with an Edelbrock, and do complete exhaust, headers to tips. Would this provide a decent improvement in performance? Do i need to have someone check the motors integrity like cylinder compressions before i do mods to be safe?

 

Check the timing. Its supposed to be set at 10* BTDC from the factory. Advance it 2 or 3 degrees. Should fix that problem a little.
The exhaust is the biggest bottleneck. Put on lobg tube headers and a 3" single exhaust or 2.5" duals for good power. The cam would be your next step. There are 2 cams recommended for the 351w that have really good results. I'm drawing a blank on both though at the moment. I'm sure someone else will pipe up

 

^^^^ What he says plus if look old replace plugs, wires, cap and fuel filter. Check fuel pressure.
Check for trouble codes even if no light on.

 

Lately I've seen several computer issues and reading this makes me think of one more possibility: could the previous owners have replaced the PCM with one that maybe isn't as compatible as what you need?

The only way I would think to tell is to use a data logger. I'd replace and investigate the other things first but maybe not rule this out. And pull the codes just to see what comes up, that never hurts.

 

Nope. It's pretty numb even when running good.
Do the upgrades like was said and you'll be happier.
The cam is quite a process so I'd just get a set of bolt on 1.7 pedistal roller rockers.
The intake sucks. Not the airbox but the intake. An edelbrock would help for sure but the cam limits your gain, and being that the intake is 600$ I'd hold off.
Or do like me... Port the 351 lower intake to accept the 5liter upper. Very nice cheap upgrade if you can do work yourself.

 

good info guys thanks. also when its running it has that strong "old farm truck" smell to the exhaust, like its burning something. any ideas?

 

It's just burning off all the crap inside and out.
Being on a farm they don't usually get to stretch their legs. So when you get it on the road and long drives, things get hot that never usually did.
No worries. Pressure wash the underside and then drive it. It will stop smelling after a while.

 

Wow your truck is having all the same problems mine is :/ I too have a 351w thats kinda sluggish on the power side and has idles rough. That smell from the exhaust, same as my truck, It smells like its running real rich

 

let me know if you find anything out. Theres a lot on my list of things to do: rotor, cap, wires, plugs, injector cleaning, fuel filter, and maybe check timing and adjust idle if possible. i will update with any improvements.

 

Do the timing first. It costs nothing. Don't touch the idle. You'll regret it.

 

I've got basically the same truck but 93 4x4. It gets on it pretty good for how heavy the truck is, but the motor and transmission have been rebuilt. You would think it is gutless though by the way I drive it, if I drove around putting the pedal to the floor I take a huge hit in MPG.

 

this is speed density,right? i wasnt sure you could change cams/rockers without making the eec cry.

 

You can change things but there are limitations to what the computer will compensate for.

 

No cats will make the exhaust stink... 351 is gutless. Downshift to go over an overpas..

 

WRONG. No cats will NOT make the exhaust stink

People please do NOT post if you have NO CLUE what you are talking about