225 slant six

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Old 01-07-2013 | 09:06 PM
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225 slant six

so I have a 74 dodge dart, and I am curious what the step by step is to make the slant engine a solid, strong, loud engine. everything on it right now is just stock. ild love to hear what you all had to say
Old 01-08-2013 | 02:15 AM
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The motor in it's stock form is a solid, reliable motor. If you are looking for more power, then I'd head over to Clifford Performance and talk to them. They've got cams, intakes, headers, and all sorts of fun imagineable for the slant 6 motors. Bore the block .030" over, throw in a mild street cam, 4 barrel intake, 500CFM carb, 6-2 header, clean up the ports in the head, install a 4spd behind it with an 8.25 rear axle and some 3.55 gears and you'll have one heck of a fun car.

Of course this is just my opinion.

First thing you should do though is figure out what you want this car to be and what you want out of it. Is it going to be a cruiser, a daily driver, a weekend driver, just for the street, mostly street and some strip, mostly strip and some street. After that, figure out what you are want to spend. "The less, the better" isn't a good answer for this. Put an actual number to it, I.E. - $1000. From there, you can figure out what you really want and what you need. There's no point in dumping all that money into the motor if the tranny or rear axle can't handle it or your brake system needs attention.
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Old 01-08-2013 | 03:51 AM
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One of the best things to do to the engine is pull the head port it & have it milled .100 , this will bump the compression up to 9.7 or so , add the super 6 2bbl intake & use a Holley 2 bbl carb , this will add a lot of power & milage potential to the engine as you have 100% tunability with the Holley 2 bby & the bump in compression really helps the power & efficiency , using some form of low restriction exhaust or even a header obviously helps too .
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Old 01-08-2013 | 08:14 AM
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Originally Posted by Chryco Psycho
One of the best things to do to the engine is pull the head port it & have it milled .100 , this will bump the compression up to 9.7 or so
That's quite a bit to take off, isn't it?
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Old 01-08-2013 | 02:21 PM
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There is plenty of meat in the head. You should also get shorter push rods if milling that much I would stick with a more modest .050 Then you could probably get away with the stock push rods
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Old 01-08-2013 | 11:26 PM
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Originally Posted by 78D200
The motor in it's stock form is a solid, reliable motor. If you are looking for more power, then I'd head over to Clifford Performance and talk to them. They've got cams, intakes, headers, and all sorts of fun imagineable for the slant 6 motors. Bore the block .030" over, throw in a mild street cam, 4 barrel intake, 500CFM carb, 6-2 header, clean up the ports in the head, install a 4spd behind it with an 8.25 rear axle and some 3.55 gears and you'll have one heck of a fun car.

Of course this is just my opinion.

First thing you should do though is figure out what you want this car to be and what you want out of it. Is it going to be a cruiser, a daily driver, a weekend driver, just for the street, mostly street and some strip, mostly strip and some street. After that, figure out what you are want to spend. "The less, the better" isn't a good answer for this. Put an actual number to it, I.E. - $1000. From there, you can figure out what you really want and what you need. There's no point in dumping all that money into the motor if the tranny or rear axle can't handle it or your brake system needs attention.
I would be using it for a daily driver, and if possible sometimes strip. I don't have a set price, because I am planning on doing one thing at a time as I save the money. any suggestions on what to do first?? where to start? thanks for all the help!
Old 01-09-2013 | 03:43 AM
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Originally Posted by kyle74
I would be using it for a daily driver, and if possible sometimes strip. I don't have a set price, because I am planning on doing one thing at a time as I save the money. any suggestions on what to do first?? where to start? thanks for all the help!
I'd just collect parts for now. Nothing sucks worse than getting into something and saying "Oh man... I wish I waited to get (that one part you really wanted). This would be the best and easiest time to install it. Dang it!"

I'm pretty sure we've all been there and have learned that a project goes much easier when we have everything we need.

I think there is a thread kicking around about planning out a project and people's opinions (or maybe just mine). I'll take a look for it.
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Old 01-09-2013 | 02:38 PM
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I have done 4 225s milled .100 & still used the stock pushrods , there is a enough adjustment available with themech cam , the later hyd cam engines are harder to work with but up to the 1983-84 range you are fine . The milled ported head makes a huge difference in power , when I did mine in an 82 D100 short box it would have trouble accerating about 65 MPH , very hard to pass on the highway . With the head & 500 CFM 2 bbl Holley even with a stock exhaust manifold but a 2" exhaust & a Turbo muffler I could easily accerate above 85 MPH . I did have to run mid grade fuel though , it would ping on reg fuel . A cam swap helps too if you are pulling the engine down that far .
Having a plan makes a lot of sense too

Last edited by Chryco Psycho; 01-09-2013 at 02:43 PM.
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Old 01-09-2013 | 03:20 PM
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Originally Posted by Chryco Psycho
I have done 4 225s milled .100 & still used the stock pushrods , there is a enough adjustment available with themech cam , the later hyd cam engines are harder to work with but up to the 1983-84 range you are fine . The milled ported head makes a huge difference in power , when I did mine in an 82 D100 short box it would have trouble accerating about 65 MPH , very hard to pass on the highway . With the head & 500 CFM 2 bbl Holley even with a stock exhaust manifold but a 2" exhaust & a Turbo muffler I could easily accerate above 85 MPH . I did have to run mid grade fuel though , it would ping on reg fuel . A cam swap helps too if you are pulling the engine down that far .
Having a plan makes a lot of sense too
what does milled .100 mean? and if I did that would I need to change anything else right away?


Originally Posted by 78D200
I'd just collect parts for now. Nothing sucks worse than getting into something and saying "Oh man... I wish I waited to get (that one part you really wanted). This would be the best and easiest time to install it. Dang it!"

I'm pretty sure we've all been there and have learned that a project goes much easier when we have everything we need.

I think there is a thread kicking around about planning out a project and people's opinions (or maybe just mine). I'll take a look for it.
so you suggest getting everything I need first? even if it takes a good amount of time to get it all.
Old 01-09-2013 | 03:56 PM
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you can swap the head alone , it will make a big difference alone if it is done right , milling .100 is machining 1/10 of an inch off the gasket surface of the head , this will increase compression substantially , I would look for an Alum 2bb intake & swap it at the same time though . the Holley 500 CFM 2 bbl could be harder to find but I have found them in wreckers also .
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Old 01-10-2013 | 03:08 AM
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Originally Posted by kyle74
so you suggest getting everything I need first? even if it takes a good amount of time to get it all.
I like to have everything I need before starting a project. You could break down the overall project into smaller projects and do the same thing For example:

You want more power. Well first you need to figure out how you want to go about doing that, then research what parts/services will help you, then prices of everything and then where you are going to get them.

Lets say you are going to mill the head .100", install a mild cam, 6-2 header, full 2" exhaust, 2bbl intake and a 500 CFM Holley carb. Well what else are you going to need?

1) Cam bearings
2) Top end gasket kit
3) Probably replace some vacuum lines and hoses while you've got stuff apart
4) Oil for breaking in the new cam
5) Maybe a new timing chain since you'll need to remove that to get the cam out
6) Thermostat and gasket as they are part of the head
7) Cylinder head bolts
8) Push rods (maybe)
9) What to do about the rockers?
10) Carb linkage
11) Spark plugs, wires and coil upgrade while I'm in there? Distributor too?
12) what does the engine shop need from me for the head? Is it cheaper if I do some of the prep work myself?
13) Valve job while the head is off?

Lets say you want to install the header yourself but you want an exhaust shop to do the rest of the exhaust, you'll have to factor that in as wel as how you plan on getting the car there. Lets say you want to hold off on the exhaust because that will put you over budget. Make the exhaust another "project".

This is a basic layout of how I go about my "projects". Yeah it sounds and looks like crazy hell, but in the long run, the project goes much smoother. You yourself don't have to do this, everyone has their own way.
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kyle74 (01-10-2013)
Old 01-10-2013 | 04:52 PM
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that list of things is exactly what I need!! because I really have no clue on the extras that you guys don't tell me. so the list helps a lot. and I like the idea of doing "projects" . like starting with power, then exhaust. that all makes since. thanks
Old 01-10-2013 | 06:39 PM
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Head bolts should be reusable , rockers should be OK too I have reused them in the past as long as the adjuster screws are tight .
You should do a full rebuild on the head , hard exhaust seats , larger valves , porting , mill the head , new guides , new valve springs & seals .
Old 01-10-2013 | 07:56 PM
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would a Holley 600cfm 4 barrel carb work on my slant 6?
Old 01-11-2013 | 02:24 AM
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Originally Posted by kyle74
would a Holley 600cfm 4 barrel carb work on my slant 6?
I think a 600 is a bit much unless you build the motor quite a bit.
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Old 01-11-2013 | 03:26 AM
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I have used the Holley 390 CFM 4 bbl on the slant with the long ram intake . I works great but needs some serious tuning as there is no heat that far away from the head
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kyle74 (01-11-2013)
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