90 351w a dog.
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From: 1007 17th ave
90 351w a dog.
I recently purchased 90 F250 with 351w & 5spd 4wd. I have done all the tune up stuff and changed all the filters. Truck runs and drives good.problem is it has no pulling power. I pull a 26ft camper with it.it is a gutless wonder pulling something. what can i do to get a little more out of this motor. different heads, intake, exhaust? i have 2 pick a part yards close by. what about all the smog crap on it. can it be bypassed.will bypassing smog crap turn on the ses light. any suggestions would be great. have you done something to your truck and worked .
Last edited by TigerDan; Sep 25, 2007 at 09:40 PM.
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From: sunny fla sometimes windy
What is the compression at? And what are you comparing it against? What gear ratio does it have? and what size tires? If the final ratio is too high due to bigger tires/stock gearing, or too high gearing to begin with and the motor is not in it's powerband it will be a dog!! You want to keep the motor between it's peak torque and it's peak horsepower rating in relation to rpm!!! A regear will probably be the biggest improvement you can make if it isn't what you need now!! if the motor comp is low new rings and a hone might bring her back to life!!
FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
Yeah... the Pre '94 motors were smothered big time. It needs a cam badly. Swap in the Comp Cams 35-255-5 and you won't recognize it. It's a bunch of work to change, but there's nothing you can do for about $200 that will have near the same inpact. Exhaust and other mods will make the most of what you got, but if it's a wheezer to begin with, itll just be a slightly peppier wheezer with a $500 exhaust system or intake.
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From: 1007 17th ave
the motor is stock ac-delco long block with 22k on it. tires are stock size Lt235-85r16. rear gear ratio 3.55. have backpressure checked cat it's ok. truck is a 5spd. only comparison i have is my old 78F250 2wd that had one very tired 400. I don't need a stroker motor.just need some more grunt. was thinking dual exhaust k&n air filter maybe msd ignition. not sure what i can do without affecting computor controls. want to get rid of a.i.r. system, but don't want ses light on either.
Hotshot
Joined: Jul 2002
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From: Bend,OR
look for some f250 axles with 4.10 gears, they should be easy to locate and drop right in place of what you have. this will help a bunch. also look into bumping the base timing up to 12* btdc with spout connector removed. get the msd coil and increase the plug gap to .55. what brand plugs are you running right now? make sure your plug wires are not touching each other and are routed properly.
a set of headers and free flowing exhaust would help a lot as well but look into gears first.
a set of headers and free flowing exhaust would help a lot as well but look into gears first.
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From: Central Mississippi
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Cargo Master
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From: British Columbia
Well he can run the truck in fourth gear on the highway instead of fifth to have about the same effect as increasing the differential ratio from 3.55 to 4.10.
I agree that the higher numerical gear ratio will improve acceleration from a stop, however.
I like Conanski's suggestion. Replacing the engine with a 94-97 engine would also be good but a big job, and possibly expensive.
I agree that the higher numerical gear ratio will improve acceleration from a stop, however.
I like Conanski's suggestion. Replacing the engine with a 94-97 engine would also be good but a big job, and possibly expensive.
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From: sunny fla sometimes windy
Driving in a lower gear isn't the same as changing the ratio!! The overall power will be better changing to a lower gear ratio(higher numerically)http://members.optusnet.com.au/~zerosin/gearcalc.html Gear calculator!!!
Keeping the motor in it's powerband will make for the best power and fuel efficency,
Pulling a trailer you need to optimize power in every gear/speed off the line to 3rd gear
will eat alot of fuel if your motor is being bogged down!! The Msd with the multiple spark/stronger spark Will probably help out, if you more completely burn your fuel you will gain power and economy!! Make your component selection based on increasing torque, it is what get's the work done!!!
Keeping the motor in it's powerband will make for the best power and fuel efficency,
Pulling a trailer you need to optimize power in every gear/speed off the line to 3rd gear
will eat alot of fuel if your motor is being bogged down!! The Msd with the multiple spark/stronger spark Will probably help out, if you more completely burn your fuel you will gain power and economy!! Make your component selection based on increasing torque, it is what get's the work done!!!
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