after reading and re-reading posts/articles here and forabiodies.com

i cant seem to figure out how the cast iron crank is bad? as noted by DD stroker article saying he is not talking about those for such a project.

im looking to improve the /6, not in the manner of earlier posts. i figured those would be down the road later on. what i thought about doing if at all possible. is losing the cast iron heads for lighter ones. would do the same for the rods but dont see anyone talk of any that might be used.

what im after is what can i do to make the stock motor better then stock. as in improving the already high gas milage the car gets. i understand some headwork is in order but what else? would a erson 254 cam help or stick with the 244 stock cam? i still dont fully understand all the jargon being used but im getting there.

maybe this a wrong train of thought, i got from the dakota forum i visit. one guy stated milage can be improved with a hp increase. he did state that if at a lower RPM the HP is up then then engine is not working as hard. using less gas that way, so how do you figure at what point to try to add power to help with milage?

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1976 Plymouth Feather Duster
2002 Dodge Dakota 4.7l v8

Changing the position of peak torque and horsepower to something that is 'useable' on the street is good for all around daily driving, that being said sometimes this will also increase your HP and or your torque over stock... but... you also have to realize that there is 'too much' of a good thing... all the components have to work together as a system...

You will not beable to retain your gas mileage with the orginal system since the engineers purpose built your powertrain to work just like that and in that rpm range and for traffic....

Just sticking in a bigger cam won't do it either... the carb will be a bit lax on doing it's job... so then you have to recalibrate it/or get a different one... but then your rear ratio is a bit steep for the engines rpm/power band (wow I daily drive in traffic @1500 rpm... but the engine make peak power at 3200...)... so then you have to change that...

There is nothing wrong with the cast crank engine from the daily driver/ and street/strip standpoint, but because all the 1960-1976 forged crank units all used interchangeable components (bearings, etc...) and you can swap the rods from the 198 onto a 225 crank and change the way the engine work... but the cast crank engine has different bearings, only came in 225 (so making a long rod motor you'll be buying some custom rods at that point...)...

Regardless of what you do, you will be able to build yourself some more 'fun' but will give up gas mileage in doing it (aka... the gret compromise... how much power are you wanting and how much mileage are you willing to give back? )


-D.Idiot



[/quote]

a) i get what your saying, im just wondering if they were for $$ reasons. were not able to get the high milage possible from this setup. would switching to ALU heads/rods then help with making the engine more eff or easier to make the same HP. now what if i just wanted to increase the HP at 3600RPM to around 110 or 125hp to see if that helps with milage. as the lower rpms will also get a small bump in hp as well. overall it would take less time for the car to get up to speed. which then should result in less fuel used.

B) ok so assum A doesnt apply. what things to the motor for stock would you do, when having it rebuildt? i read about having the values on the head worked on but how so?

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1976 Plymouth Feather Duster
2002 Dodge Dakota 4.7l v8

Good luck on getting your hands on an aluminum head or aluminum rods. While al heads exist, they were prototype only and very rare to find. There have never been, to my knowledge, any type of aluminum rod. I don't think you'd want to run that type of rod anyway as they are for race applications.

I'd start with the Super Six system, possibly convert to HEI, change the cam, possibly mill the head or block for a touch more compression, and switch to dutra duals for a mild street build like it sounds like you are going for. I'd do some searching of past threads and research the topic that way.

well with ALU i figured the lighter weight would help as well. im thinking highway milage not city. if i lose city milage no biggie, im going on the basis that lower RPM = less gas used. now if i switch to a A500 trans, with the same rear. lets just say it takes 100HP to keep the duster moving at 60mph. according to allpar it makes 100HP@3600RPM, now i figure to increase HP. there for lowering the RPM at which 100HP is made to keep the car moving at 60mph. i guess i need to look at the rest of the powertrain first then look at the engine. i guess what i need to know is what power is needed for the car to stay at 60mph. then increase and shift the power to the low/mid range. with the OD hope to keep the RPMs closer to the needed (if needed) 100hp. to keep the car moving at that speed. i guess im looking at this from another direction then others for tring to do this. i used online calculators to see what rpm with the rearend gears to get 60mph. something seems off to me as according to one it says for my rear at 3500rpm speed would be 44mph. umm how, i my qustion...

i have read and read all over, still dont fully get what some do. only to find my self asking the same questions and not finding answers. I guess if all else fails i will followe what they did in the 99 mopar mag for a 232ci/237HP slant six. then try to change it to fit the power i need in the right section of the RPM range.

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1976 Plymouth Feather Duster
2002 Dodge Dakota 4.7l v8

Evilsizer,

I tried to rebuild my engine with the same concept of building more low end, low rpm torque and turn taller gears to keep rpms low for better mileage and not have a slug on my hands or a high rpm racer. I doubt that I have gained that much horsepower but through careful tunning and mods during the rebuild I have created what I wanted which was a torque monger at low rpm. It has an amazing amount of low end snap compared to the stock engine and gets good mileage even using 10% ethanol. Others on this forum are building race engines or modified street motors with more HP in mind. I have done the opposite which has taken me down another path.
Take a look at the engine build matrix section for my engine build.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG