5.9L Magnum build with questions

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black954

black954

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I just picked up my engine yesterday and I was able to get it torn down today. It’s a 5.9L Magnum out of a 1999 Dakota R/T with 114,000 miles on it. My plan is to do a mild refresh and put the original 4-speed behind it and put it in my 69’ Dart Swinger for a few years. I’m planning on reusing the original rods/pistons/crank and installing a cam, intake, long tubes topped off with a Holley Sniper EFI. I tore the the engine down today and everything looks pretty good. Bearings show some wear but nothing bad. At this point, I will order stock sized main and rod bearings as well as stock bore rings. I’m bringing the block to the machine shop to have it hot tanked and new freeze plugs and cam bearings installed. When I get it back, I’ll hone the cylinders and clean up the deck surfaces. Im considering 2 options.
Option 1 is having the original heads rebuilt, off the shelf cam with matching valve springs, stock rockers, Performer RPM Air Gap intake.
Option 2 is getting new heads that work with the stock rockers and LA bolt pattern, off the shelf cam, LA single plane intake (that can be used with the 340 down the road).
My question is what is the biggest off the shelf cam I can run with each option with a basically stock short block? Also, what are my options with bolt on replacement heads that will work with option 2?
I’m not going all out super low budget on this, but I want something that will go together pretty easily with off the shelf parts. Also, I’m running manual brakes so a good idle or good vacuum is of no priority to me. I just don’t want to spend a ton of money on an engine that will only get replaced in a couple of years. At the same time, I’d like something fun in the time being. And a power band up to 6,000-6,500 would be a huge plus.

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Hughs has cams that will work with over 0.500 lift on stock heads and rev to 6500.
 
If you keep the lift on the low side, Hughes Engines has a trick retainer and spring set for the Magnum heads that allow a .540 lift. How long the valves hang open is more of a concern. A long duration cam is part of that issue.

On the cylinder heads, there are two heads available. The iron EQ or the other make which the name escapes me at the moment. But, again, Hughes engine s has these iron heads. OR the new Trick flow heads. Way pricey by compare BUT a massive ability to take you much further down the performance line since it’s performance ceiling is way way higher.

Besides the TF heads cost, they are set up for both engine series. There is one caveat to this. The rockers used are, of course, pricey and designed to ether purchase for the Magnum or LA style.

You didn’t t mention gear ratio or the cars weight and tire size. So a cam is hard to recommend. Another thing about a cam and how well it operates and how long in RPM terms it delivers power would be the cylinder heads. Stock port limit RPM potential and well ported aftermarket heads allow more than advertised RPM.

Also, is this car to be a daily or often driven? In what conditions?

Once you make a head choice, a cam choice gets easier.
I wouldn’t rebuild the OE heads. I would just use them as is, stock, with a Hughes Engines trick spring kit and a mild cam. Or move right to the trick flow heads and never look back.
 
Did it run before being torn apart?

I'd have been tempted to leave it alone.

114,000 is between "broken in" and "seasoned" on a Magnum.

Mine runs just as good at 167,000 as it did when I bought it at 30,000.


Lunati has a roller cam with a 1.6 rocker ratio lift of .517

Everything I've read says the theoretical max lift on Magnum heads before you need to mill the guide boss is .520

IIRC there is also a cam available with .513 lift.
 
CUDA69 said:
Hughs has cams that will work with over 0.500 lift on stock heads and rev to 6500.
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This is kinda what I am looking for
rumblefish360 said:
If you keep the lift on the low side, Hughes Engines has a trick retainer and spring set for the Magnum heads that allow a .540 lift. How long the valves hang open is more of a concern. A long duration cam is part of that issue.

On the cylinder heads, there are two heads available. The iron EQ or the other make which the name escapes me at the moment. But, again, Hughes engine s has these iron heads. OR the new Trick flow heads. Way pricey by compare BUT a massive ability to take you much further down the performance line since it’s performance ceiling is way way higher.

Besides the TF heads cost, they are set up for both engine series. There is one caveat to this. The rockers used are, of course, pricey and designed to ether purchase for the Magnum or LA style.

You didn’t t mention gear ratio or the cars weight and tire size. So a cam is hard to recommend. Another thing about a cam and how well it operates and how long in RPM terms it delivers power would be the cylinder heads. Stock port limit RPM potential and well ported aftermarket heads allow more than advertised RPM.

Also, is this car to be a daily or often driven? In what conditions?

Once you make a head choice, a cam choice gets easier.
I wouldn’t rebuild the OE heads. I would just use them as is, stock, with a Hughes Engines trick spring kit and a mild cam. Or move right to the trick flow heads and never look back.
Click to expand...

Sorry, I should have mentioned the car I’m putting it into. I’m building a 69’ Dart Swinger. 3.55 gears, 25.5” tires, 4 speed, manual brakes. I’m building it as a road race but street legal car. I don’t really care about street manners either. It will get a windage tray and Milodon road race pan as well. I’ll also but the thinner head gaskets on it to bump the compression with the stock pistons.
 
YY1 said:
Did it run before being torn apart?

I'd have been tempted to leave it alone.

114,000 is between "broken in" and "seasoned" on a Magnum.

Mine runs just as good at 167,000 as it did when I bought it at 30,000.


Lunati has a roller cam with a 1.6 rocker ratio lift of .517

Everything I've read says the theoretical max lift on Magnum heads before you need to mill the guide boss is .520

IIRC there is also a cam available with .513 lift.
Click to expand...
I was tempted to run it as is as well, the bores looked perfect and it was an untouched relatively low mile engine. That’s really why I figure I’d throw a cam in it and thinner head gaskets to try and get more RPMs and some more power out of it. The bearings did show some wear so thats why I’m replacing them. I could have ran the original rings, but I have a hard time slapping them back in when I can clean them and file fit new rings while its all apart. I’m still having a hard time reusing the roller lifters, but I think I will after reading so many successful stories of people reusing them.
 
I can’t recommend a road race cam. To many variables.
 
Well I had an interesting morning. I dropped the block off for cleaning and then he’s going to hone it and install new freeze plugs and oil plugs. Then i made a call to IMM and talked to Brian. Apparently the good EQ magnum heads haven’t been available for some time leaving the only option to run my original heads or replacement OEM castings. I just can’t see spending that kind of money on iron heads with no performance increase. SO, I went with the following. Basically mimicking the Hot Rod 455hp Magnum build, I’m going with a very similar set up. I ordered IMM’s aluminum heads with 2.02/1.60 SS Manley valves, clearanced pushrod tunnels, etc. along with their SS adjustable shaft rockers made to oil with pushrod oiling. I also went with the Icon forged direct replacement pistons. Lastly, I went with the hyd. Roller camshaft Brian recommended with a wide powerband from 2,200-6,200. This set up will give me approx. 10.2CR, a stronger valvetrain, stronger pistons, dropping a lot of weight off the front end, etc. I don’t have the exact cam specs, but it’s around 234/239, .600” lift on a 110LSA. I will post up the specs when it arrives. When the pistons arrive, I’ll bring in the rods to have them installed and bring in the crank to be cleaned and polished. The only real tedious work ill have to do is file fit the rings and measure for pushrods. I’ve done both of those in the past so I should be ok doing that. I guess things escalated quite quickly LOL
 
Good choice. I think you will be very happy with it. Please post updates as you go. I like the direction this one is going.
 
I do not, I guess they’re new. They were price wise below TF and Edelbrocks but flow better then the Edelbrocks. I’m not interested in porting right now, but they will be good for future head porting. Plus they pair well with the Victor 340 intake
motorpirate said:
Got a link for the IMM aluminium heads???
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Bobzilla said:
Good choice. I think you will be very happy with it. Please post updates as you go. I like the direction this one is going.
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Oh I will for sure. I like posting progress reports and pics so you’ll see where it’s going. I kinda rushed to order everything because of everything going on now and I want to have the best chances of driving the car this summer
 
black954 said:
I do not, I guess they’re new. They were price wise below TF and Edelbrocks but flow better then the Edelbrocks. I’m not interested in porting right now, but they will be good for future head porting. Plus they pair well with the Victor 340 intake
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Their website doesn't even show them..
Mind if we ask the cost??
 
Sounds like a nice build. Make sure you speak with Brian about pin weights to keep the Icon pistons at factory weight. This will avoid having to balance.....unless you want to.
 
JoePole1 said:
Sounds like a nice build. Make sure you speak with Brian about pin weights to keep the Icon pistons at factory weight. This will avoid having to balance.....unless you want to.
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We did talk about that. He swaps out the pins that come with the Icon’s so that you do not need to balance the rotating assembly. Only thing I have to do is file fit the the top rings.
 
See what your machinist is going to charge you to put the icons on the stock rods and r&r them. It may close enough in price to just go with the scat i beams. they are lighter than stock thus requiring a balance, but if youre going to spend the money why not spend it on upgrades.
 
turboking15 said:
See what your machinist is going to charge you to put the icons on the stock rods and r&r them. It may close enough in price to just go with the scat i beams. they are lighter than stock thus requiring a balance, but if youre going to spend the money why not spend it on upgrades.
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He quoted me $55 to swap pistons which I didn’t think was too bad. That’s still quite a bit cheaper then rods and balancing. I appreciate your idea because it’s a good suggestion. The only reason I went with the Icons is because they are a direct swap for the stock pistons, plus they have valve reliefs allowing me to run a much better cam, and because they increase compression a whole point. That was just too many benefits to not using the stock pistons. Plus I’d spend hours cleaning the original pistons so I’m saving time as well.
 
If you plan on reusing the factory rod bolts then i guess that would be the way to go. Most guys opp for arp hardware at that point and new rods are almost the same price by the time you recon the rods and buy hardware.

What did the icons run you with the needed pin if you dont mind me asking?
 
turboking15 said:
If you plan on reusing the factory rod bolts then i guess that would be the way to go. Most guys opp for arp hardware at that point and new rods are almost the same price by the time you recon the rods and buy hardware.

What did the icons run you with the needed pin if you dont mind me asking?
Click to expand...
Apparently the stock 3/8” rod bolts don’t have issues like in other engines with smaller rod bolts. But yes you are correct. If I were to upgrade to ARP rod bolts, then I’d be paying to resize the rods and at that point, I’d upgrade to the Scat rods for sure. The Icon forged pistons with upgraded pins and rings were $750. I’d knock $100 off that just because I’d have to buy new rings anyway.
 
IMO, your in good hands with Brian over at IMM.

If you can find out the slugs part number, post it up please.
 
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