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Discussion Starter · #1 ·
hey guys i have a 400bb with a 727 and 203 i am running 355gears, and 33" tires on 15" rims, when i am on the highway driving i can only get to about 60 on the speedometer witch is actually 65mph but i am running around 3,000-3200 rpms, this seems high, that and i have my foot in the floor while acheiving this, so there is no more go, what rpm should it be running at and what are the cures for this ailment? also i would like to but a full seal kit into the tranny but i can't find a diagram anywhere, does anyone have one and if so could you email it to me, [email protected]
 

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Seeems like u have met the end of the power band on the engine ...... this engine fairly fresh or got omse hard mileagae on it ? do a compression check .... decent tune up ... soulds like the engine is under performing for sure ..... granted it should snap up to about 4,500 rpms with no problem .... just for fun got any of the fctory size rubber and riums laying around ? But i think it's just your engine being worn out more than likely ....
 

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Mine does the same. I run 32"'s and I turn 3,000 @ 65mph. Anything much past that and it gets a little funky. It's just a worn engine prolly. I know that's what mine is. They were not power houses even when new. You also have to remember that these truck were designed when the speed limit was only 55mph.
 

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the CARB is running lean at that RPM so it wont rev any higher
 

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Discussion Starter · #5 ·
ok so what can i do to freshin up the motor, besides a total rebuild? i have thought about new rings and a cam, right now i am running a little two bbl carb but have a 4bbl intake just looking for a good "cheap" 4bbl to put on it.
also the tranny had been sitting since 1996 without moving, and i just threw it in, could it be my tranny?
 

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Total overhaul! Stroke it!!! ;D It's possible you could have some tranny slip too I guess.
 

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DODGEBOYS said:
the CARB is running lean at that RPM so it wont rev any higher
Could also be not enough or too much spark advance (timing).

What is your initial and total (initial + mechanical) advance set at?

Are you sure about the gear ratio? For the speed you posted, with 33" tires and 3.55 gears I come up with about 20% trans slippage---which is a LOT.

-SM
 

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sounds like more than a tired engine, but then again, how many hundred thousand are on it. I had a '74 400; and at 160-180K miles it would still turn over 6K. Mine had a fresh set of heads put on it around 160K; and freshened up completely after it suffered a major fever several times and bent a rod.
A 400 should turn 33's with 3.55's with no problem and I would think better cruising than that.
Make sure the motor is in good shape and look more at the tranny. Try adjusting the bands.
Aaron
 

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Just a guess, but have someone put the pedal to the floor and see if the throttle blades are openning all the way.
 

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Discussion Starter · #11 ·
ok had the father in law look at it and well he says the torque converter is shot, so i think that means that the tranny is slipping right? and the motor only has around 5,000-6,000 miles on it before the previous owner died, so it sat from 1982-2002 without moving much, however when i found it i hooked up an electric fuel pump and battery to her and she fired after only turning for a few seconds, the tranny has sat under water for a bout a month that i know of, leaks like a sive, and i have rebuild plans for it, so does anyone have the right rpm setting for 65mph on this motor and what torque converter will be the best and cheapest for daily driver and trail running
 

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The rpms you are turning would be correct for a truck with 4.10's and 33's at that mph. The trans sitting under water is not good, did you change the fluid? your problems may all be in the trans, needless to say the 400 will run much better with a 4 brl then that under feeding 2 brl
 
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