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225 Slant Six

Mopar Muscle
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225 Slant Six

Philip009 Philip009
New User | Posts: 7 | Joined: 08/13
Posted: 08/30/13
01:58 AM

Hello everyone,

I have a 225 Slant Six (rebuild engine) with a one barrel carb and was wondering how good is it on gas?
I would like some info/input about it. I've heard great and wonderful of how the Slant Six is a very durable engine but I would like to know what I'm getting for MPG since it's not a powerful engine and I have only a one barrel carb on it.

By the way, The gas gauge and odometer isn't working at the moment and I will have it fixed as soon as I get the extra cash but for the mean time I'll try to get some info.  

waynep712222 waynep712222
User | Posts: 127 | Joined: 04/13
Posted: 08/30/13
08:16 AM

welcome to the forums...

mileage calculations require a few things... knowing how far you have driven..  and how much gas it took to fill your tank to the exact same spot...

you could use a GPS device to track exactly how far you have driven....

checking the speedo issues and the gas gauge issues are both started under the car...

gas gauge... unplug the sending unit from the tank.. the gas gauge should swing all the way in one direction when you turn the key on..    when you touch the wire you removed from the sending unit to ground with the key on.. the gauge should swing the other directly... this proves the gauge and wiring are intact.. and the problem is at the sending unit or tank ground connection...  this is the starting point of all fuel gauge diagnosis..

does the speedo show the speed you are going but not the miles driven..
if so. then the issue is with the speedo head in your dash...

if you don't get speed indications from the speedo while you are moving... follow below..

the speedo is also checked from under the car.. middle of the car.. drivers side.. on the tail housing of the transmission there is a cable that is screwed to the side..  loosen the nut on the end of the speedo cable ... pull the speedo cable of the transmission...  with a friend in the drivers seat... and your fingers.. spin the speedo cable core.. the square ended flex cable.. does it turn easily with your fingers..   if so... spin it in one direction.. does the helper see the speedo needle move??? spin it the other way also..

again.. if the speedo needle moves.. then the speedo and cable are OK.. and the issue might be with the speedo gear in the transmission...

there is something you might want to check.. if the transmission was removed at the time the engine was rebuilt..   the speedo gear holder needs to be rotated to one of the positions that match the gear count of the gear...

its possible that the speedo gear holder just did not get rotated to the proper position to engage the teeth.... or it got installed too tight and damage might have happened...

as for power from the slant six... or fuel economy... that depends on how the carb works.. and how the distributor works...  there are a bunch of things that can be done...

an electronic ignition conversion...

hopefully the plastic distributor drive gear was replaced when the engine was rebuilt..

depending on which carb you have.. and its possible to have several.. and when it was last rebuilt..  these are fairly easily to rebuild..

lastly.. on the exhaust manifold.. there is a heat riser valve.. its a weight on a shaft.. that needs to be free to rock thru its partial turn.. if its seized in place.. it can effect your power and fuel economy... don't touch it when the engine has been run.. only cold.. don't want to burn your hands...  

waynep712222 waynep712222
User | Posts: 127 | Joined: 04/13
Posted: 08/31/13
01:21 PM

by the way.. there are several articles scattered thru the magazine on the slant six..

you might find them enjoyable..  

Philip009 Philip009
New User | Posts: 7 | Joined: 08/13
Posted: 09/03/13
01:18 PM

Thank you very much! This is all useful information to me and will definitely use it this week! Thank you for the reply.