the stupid kids magnum build idea

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carmart1975

carmart1975

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Hey, it’s the dumb kid again. After all this time, I finally got the bottom end done on my Magnum and I’m getting ready to do the top end. I got some new used Magnum heads that are not cracked, and I’m going to send them out to get rebuilt. I would just like some clarification on my build.

I am doing a /6 to V8 swap in my Duster, and the goal is to have a fun street car on a budget. Right now, the motor has a stock bottom end with new OE .030-over pistons and ARP rod bolts. Like I said, I have some fresh OEM heads that I will be putting on.

Being the teen I am, I want the best cam that money can buy. I am thinking about getting the Hughes Whiplash cam with their spring kit. I will reuse the roller lifters I have because they are in perfect condition, and I will buy the longer pushrods for the new cam from Hughes Performance.

This motor will also be running an LA front cover setup to use V-belts. It will be a carbureted setup with a China Air Gap intake. Also, correct me if I’m wrong, but I was told I can reuse my factory high-stall torque converter.

Let me know if you think this is all a good idea.
 
carmart1975 said:
Hey, it’s the dumb kid again. After all this time, I finally got the bottom end done on my Magnum and I’m getting ready to do the top end. I got some new used Magnum heads that are not cracked, and I’m going to send them out to get rebuilt. I would just like some clarification on my build.

I am doing a /6 to V8 swap in my Duster, and the goal is to have a fun street car on a budget. Right now, the motor has a stock bottom end with new OE .030-over pistons and ARP rod bolts. Like I said, I have some fresh OEM heads that I will be putting on.

Being the teen I am, I want the best cam that money can buy. I am thinking about getting the Hughes Whiplash cam with their spring kit. I will reuse the roller lifters I have because they are in perfect condition, and I will buy the longer pushrods for the new cam from Hughes Performance.

This motor will also be running an LA front cover setup to use V-belts. It will be a carbureted setup with a China Air Gap intake. Also, correct me if I’m wrong, but I was told I can reuse my factory high-stall torque converter.

Let me know if you think this is all a good idea.
Click to expand...

Are you using an electric or mechanical fuel pump?

If you are using a mechanical one make sure the cam can take the eccentric used to activate the fuel pump arm.

By pass hose from intake to water pump is a ***** to install due to the different angle from the aftermarket intake.

Pay attention to pully alignment if using V-Belt setup.

Post some pics!!
 
According to Hughes, the stock converter can be used but I would suggest increasing the converter stall speed to meet the need better. The problem being is the factory converter stall speeds vary. I know this is a bit pricey and you MAY not need to do this.

What is the stall speed of this “Factory High Stall Converter?
What is your gear ratio and tire size you will be using?
These are a key thing to know.

The OEM Magnum head is OK for general purpose use and will allow good power.

The best cam money can buy is a cam that first your performance parameters. No one grinder is better than another.

I only suggest getting a cam with as much lift as your heads flow. If flow stalls at .500 lift and then goes down in flow, lift it to .500. If the flow rate hangs on, leave it at .500 and just hold the valve open longer which is more duration and pushing the power band upwards.

Are you using the Hughes roller whiplash cam?
 
buy the spring kit and cam snout extension (if using a mechanical pump) from hughes.

send your original cam out to be reground. i highly suggest Ken at Oregon Cams. email him and get the conversation going, he'll want the engine specs, converter and gear ratio and then make a few suggestions of which cam would suit your build best.

if your converter is neutral balance you can use it, you'll need either the factory 5.9 flex plate or the aftermarket B&M one to match it all up.
 
I don't see where Hughes offers a Whiplash roller cam.
 
If money is tight you can always upgrade converter later or install cam and converter later.

Everything don't have to be perfect from the start, I'd worry what's needed for the swap any performance mods are a bonus, once it's in you can dial in the drivetrain/combo.
 
Great advice given so far. My question.....is your Magnum a 5.2 or 5.9? If it's a 5.9, you will need to use a flex plate from a 5.9 to keep the assembly in balance. You will also need a harmonic balancer for a 5.9 that will accept V pully's. Using the China Gap intake, you won't have any problems using an LA water pump and bypass hose since you're using an LA timing cover. If you choose to buy a new hydraulic roller cam vs getting your old one reground, be sure to buy one that has a long snout on it. That way you can use an LA fuel pump eccentric instead of the Hughes adapter. That adapter works, and I have one on my 273......BUT, it just looks kinda Mickey Moused to me because the woodruff key barely hits one end. I used a quart of Red Loctite and tightened the bolt one click shy of wringing the head off in hopes it will hold. Good luck with the rest of your build.
 
So
Super-Cuda said:
Are you using an electric or mechanical fuel pump?

If you are using a mechanical one make sure the cam can take the eccentric used to activate the fuel pump arm.

By pass hose from intake to water pump is a ***** to install due to the different angle from the aftermarket intake.

Pay attention to pully alignment if using V-Belt setup.

Post some pics!!
Click to expand...
should have said that i was going to run a electric pump my bad and i will for sure post pics when its done and when its in the car i will send pic of the short block now
 
rumblefish360 said:
According to Hughes, the stock converter can be used but I would suggest increasing the converter stall speed to meet the need better. The problem being is the factory converter stall speeds vary. I know this is a bit pricey and you MAY not need to do this.

What is the stall speed of this “Factory High Stall Converter?
What is your gear ratio and tire size you will be using?
These are a key thing to know.

The OEM Magnum head is OK for general purpose use and will allow good power.

The best cam money can buy is a cam that first your performance parameters. No one grinder is better than another.

I only suggest getting a cam with as much lift as your heads flow. If flow stalls at .500 lift and then goes down in flow, lift it to .500. If the flow rate hangs on, leave it at .500 and just hold the valve open longer which is more duration and pushing the power band upwards.

Are you using the Hughes roller whiplash cam?
Click to expand...
The factory high stall is a 2200 thats what i saw in my chassis manual i do have 3.21 gears but for sure going to do 3.55s eventually with time and a sure grip not sure in the tire size yet right now i have 215/70/14 but for sure want to get a 15in wheel and and more meat and cam wise i want the hughs whiplash like you stated.
 
JDMopar said:
Great advice given so far. My question.....is your Magnum a 5.2 or 5.9? If it's a 5.9, you will need to use a flex plate from a 5.9 to keep the assembly in balance. You will also need a harmonic balancer for a 5.9 that will accept V pully's. Using the China Gap intake, you won't have any problems using an LA water pump and bypass hose since you're using an LA timing cover. If you choose to buy a new hydraulic roller cam vs getting your old one reground, be sure to buy one that has a long snout on it. That way you can use an LA fuel pump eccentric instead of the Hughes adapter. That adapter works, and I have one on my 273......BUT, it just looks kinda Mickey Moused to me because the woodruff key barely hits one end. I used a quart of Red Loctite and tightened the bolt one click shy of wringing the head off in hopes it will hold. Good luck with the rest of your build.
Click to expand...
Its a 5.9 thanks for the info
 

carmart1975 said:
The factory high stall is a 2200 thats what i saw in my chassis manual i do have 3.21 gears but for sure going to do 3.55s eventually with time and a sure grip not sure in the tire size yet right now i have 215/70/14 but for sure want to get a 15in wheel and and more meat and cam wise i want the hughs whiplash like you stated.
Click to expand...
I don't know where you're getting your information, but a 2200 converter in a Mopar is stock If that's what you go with, you'll be sorely disappointed.
 
RustyRatRod said:
Me too, because they don't list a Whiplash roller, unless I missed it.
Click to expand...

IMG_4997.jpeg
 
JDMopar said:
Great advice given so far. My question.....is your Magnum a 5.2 or 5.9? If it's a 5.9, you will need to use a flex plate from a 5.9 to keep the assembly in balance. You will also need a harmonic balancer for a 5.9 that will accept V pully's. Using the China Gap intake, you won't have any problems using an LA water pump and bypass hose since you're using an LA timing cover. If you choose to buy a new hydraulic roller cam vs getting your old one reground, be sure to buy one that has a long snout on it. That way you can use an LA fuel pump eccentric instead of the Hughes adapter. That adapter works, and I have one on my 273......BUT, it just looks kinda Mickey Moused to me because the woodruff key barely hits one end. I used a quart of Red Loctite and tightened the bolt one click shy of wringing the head off in hopes it will hold. Good luck with the rest of your build.
Click to expand...

Oh trust me... its a real ***** to get an LA bypass hose to attach from an air gap intake to the 70's style water pump!.

The outlet from the intake comes straight out and is not angled as the LA intake is.

Here's my LA setup with v belts on a Magnum 5.9 engine.

If you have an alternative, I would be grateful if you would post it with a part number.


1772198621826.png


SEE THE DIFFERENCE ?


1772198745857.png
 
Super-Cuda said:
Oh trust me... its a real ***** to get an LA bypass hose to attach from an air gap intake to the 70's style water pump!.

The outlet from the intake comes straight out and is not angled as the LA intake is.

Here's my LA setup with v belts on a Magnum 5.9 engine.

If you have an alternative, I would be grateful if you would post it with a part number.


View attachment 1716514918

SEE THE DIFFERENCE ?


View attachment 1716514920
Click to expand...
The difference is, you bought nice Edelbrock Magnum heads and an Edelbrock Magum Air Gap intake. Your bypass outlet is straight, so it will fit a Magnum water pump. I bought an aluminum Chinese Airgap made to fit either an LA head or a Magnum head. The bypass outlet on this intake I bought just to have in stock because it was cheap, comes out at an angle like an LA intake would. If I were to put this intake on a Magnum motor with the Magnum water pump, I would be experiencing the same pain in reverse…lol. The young OP of this thread said he is using an LA timing cover and water pump, plus an intake like in the pic below. That is why I said he would have no problems. I guess if we try to cross breed intakes and water pumps in either direction with either intake, one end of the bypass hose or the other is gonna bite us in the butt!

DEB4CBB0-0278-483F-B258-27D0C68E05B0.jpeg
 
JDMopar said:
The difference is, you bought nice Edelbrock Magnum heads and an Edelbrock Magum Air Gap intake. Your bypass outlet is straight, so it will fit a Magnum water pump. I bought an aluminum Chinese Airgap made to fit either an LA head or a Magnum head. The bypass outlet on this intake I bought just to have in stock because it was cheap, comes out at an angle like an LA intake would. If I were to put this intake on a Magnum motor with the Magnum water pump, I would be experiencing the same pain in reverse…lol. The young OP of this thread said he is using an LA timing cover and water pump, plus an intake like in the pic below. That is why I said he would have no problems. I guess if we try to cross breed intakes and water pumps in either direction with either intake, one end of the bypass hose or the other is gonna bite us in the butt!

View attachment 1716515003
Click to expand...


Got Ya!

Thanks for the post.

Now it makes sense!
 
JDMopar said:
The difference is, you bought nice Edelbrock Magnum heads and an Edelbrock Magum Air Gap intake. Your bypass outlet is straight, so it will fit a Magnum water pump. I bought an aluminum Chinese Airgap made to fit either an LA head or a Magnum head. The bypass outlet on this intake I bought just to have in stock because it was cheap, comes out at an angle like an LA intake would. If I were to put this intake on a Magnum motor with the Magnum water pump, I would be experiencing the same pain in reverse…lol. The young OP of this thread said he is using an LA timing cover and water pump, plus an intake like in the pic below. That is why I said he would have no problems. I guess if we try to cross breed intakes and water pumps in either direction with either intake, one end of the bypass hose or the other is gonna bite us in the butt!

View attachment 1716515003
Click to expand...
How is the quality of your Chinese air gap?
 
This is a street driven car so please do not overcam your build thinking you are drag racing at wide open throttle rather than driving to the cruise in
Small blocks like split lift and duration cams
the max i would go would be specs like a racer brown SSH 25-44
you need a good converter, stock won't work well at all
resist the think that you need 3.55s
3.23s with a good converter will work wayyyyyy better than 3.55s
 
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