5.9l magnum swap questions

[KevinB]

Hi all, I've come to the conclusion it makes no sense to beef up my 318 when for cheaper I could rebuild a magnum 360 and get more hp. So I'm pretty much all in at this point lol

This is for my 66 Dart by the way

So two questions...

1. Knowing the cracked head issue, and assuming I get a running 5.9 from a junkyard with a small warranty on it, and assuming the heads aren't cracked, should I go for the EQ heads as a preemptive measure? Or should I save my money for now and replace them when one cracks? I'm more interested in durability and cost than performance from the 5.9.

2. I understand a custom cam grind is the most common route...I've seen the following specs listed as a potential grind but I believe it was going on a motor using NOS. Does this grind make sense for a run of the mill mild but kinda choppy running 5.9?

adv. duration: 276 282
dur @ .50: 224 230
valve lift: .513 .513


Other specs for reference:

Block work: Tank, mag, hone
650cfm carb
Crosswinds air gap knockoff intake
stock pistons and rockers
New cam and main bearings
new timing set
new lifters and rods
TTI headers
3.73 or 3.41 rear end (still debating)

 

[gtsdude]

If the heads you end up with are not cracked I would run them, in fact a lot of high mileage magnums are more that likely cracked and run just fine, but it doesn't make sense to spend any $ on set already cracked. On the cam, what is the other specs?

 

[Blind Squirrel]

Put "NO" faith in the small warranty. Yards require a very specific set of requirements be met before they will honor that warranty. Some require that the motor have certain items replaced and some have a requirement that they be installed by a professional mechanic. Not that any of that should make you steer clear of them but its caveat emptor going in.

 

[KevinB]

If the heads you end up with are not cracked I would run them, in fact a lot of high mileage magnums are more that likely cracked and run just fine, but it doesn't make sense to spend any $ on set already cracked. On the cam, what is the other specs?

Well other than checking the oil for coolant, how else would I know if the heads in a junkyard engine are cracked?

As for the cam, that's all that was mentioned in the thread I found

 

[gtsdude]

Well other than checking the oil for coolant, how else would I know if the heads in a junkyard engine are cracked?

As for the cam, that's all that was mentioned in the thread I found

Are you doing a full rebuild or just changing out the cam and running it? If doing a rebuild have the heads checked for cracks. Usually a cam in the 230 or so @ 50 will have a little lump to it, the overlap and LSA play a big part in that as well.

 

[KevinB]

Are you doing a full rebuild or just changing out the cam and running it? If doing a rebuild have the heads checked for cracks.

Yes full rebuild, the heads will def get checked if I'm going to try to use them...I guess I was responding to your statement of no point in spending money on cracked heads...my feeling is there's not an easy way to know unless you spend the money...unless someone has a suggestion

 

[Dustert73]

I've also heard about how the cracks can be fixed with new valve seats. But honesty I'm sure majority of magnums running and driving just fine on the road right now have at least one cracked head.

Not sure if it has been mentioned yet, but the front timing chain cover/front dress will need to be changed to la fashioned stuff.

 

[KevinB]

I've also heard about how the cracks can be fixed with new valve seats. But honesty I'm sure majority of magnums running and driving just fine on the road right now have at least one cracked head.

Not sure if it has been mentioned yet, but the front timing chain cover/front dress will need to be changed to la fashioned stuff.

As I understand it that's only if you want to use a mechanical fuel pump, I'm debating this right now. I really prefer serpentine setups and this would be an easy way to have one...just don't know if it's worth the change to an electric pump

 

[Dustert73]

Yes full rebuild, the heads will def get checked if I'm going to try to use them...I guess I was responding to your statement of no point in spending money on cracked heads...my feeling is there's not an easy way to know unless you spend the money...unless someone has a suggestion

On my set of mag heads I can literally just see the crack. Pay extra attention to between the valve seats

 

[KevinB]

On my set of mag heads I can literally just see the crack. Pay extra attention to between the valve seats

If you have a photo that would be super helpful

 

[KevinB]

So if cracked heads are an inevitability, shouldn't I just plan to build with the EQ heads? Btw my engine shop said he'd give me a credit towards labor if I have him the stock heads

 

[RustyRatRod]

I would locate an LKQ in your area. They only warrant known good running engines. That means there is less of a chance you will run into something cracked. I think they warranty the engine as a whole and if you disassemble it, you void the warranty.

Big whoop. If it was runnin good, you will probably not have anything cracked. I got my 1999 5.0 Explorer engine for the RobKat for 300 bucks. It had a 6 month warranty, because it was a good running engine. I tore it down and it was super clean on the inside. It was so clean I redid the heads myself and put some good springs on, and reassembled the engine with new rings and bearings. Never saw the machine shop.

You will be money ahead doing the same thing.

 

[RustyRatRod]

So if cracked heads are an inevitability, shouldn't I just plan to build with the EQ heads? Btw my engine shop said he'd give me a credit towards labor if I have him the stock heads

That would be smart, yes.

 

[Dustert73]

As I understand it that's only if you want to use a mechanical fuel pump, I'm debating this right now. I really prefer serpentine setups and this would be an easy way to have one...just don't know if it's worth the change to an electric pump

http://www.magnumswap.com/

Look around on there ^ it'll probably answer a lot of questions

 

[PhillH]

If you go to a pick and pull, where you pull the engine yourself verses buying one from a yard that you buy it off the shelf already pulled. Keep this in mind, a wrecked car had to have been running when it got hit, whereas a straight car probably came to the yard because the car needed to much work, likely the engine.

 

[KevinB]

http://www.magnumswap.com/

Look around on there ^ it'll probably answer a lot of questions

Yes that site is what helped me make up my mind. I don't feel like what I'm asking is really covered there though. Esp the cam question

 

[gtsdude]

I am planning on picking up a 5.9 myself to put on the stand, just a rering, bearing and hone job if all checks out ok. If the heads are not cracked I am using them as well. My post about spending $ on cracked heads, I meant valve job, new springs etc. Sometimes you can clearly see the crack between the seats and sometimes you cant, that's where you have them checked, its not that expensive. Here is a pic from this site. On the cam we need more info, like LSA, overlap etc.

 

[KevinB]

I am planning on picking up a 5.9 myself to put on the stand, just a rering, bearing and hone job if all checks out ok. If the heads are not cracked I am using them as well. My post about spending $ on cracked heads, I meant valve job, new springs etc. Sometimes you can clearly see the crack between the seats and sometimes you cant, that's where you have them checked, its not that expensive. Here is a pic from this site. On the cam we need more info, like LSA, overlap etc.

I see what you mean now...I guess if the heads are ok I'll just go with it and swap later if need be. Thanks! Any thoughts on custom cam specs?

 

[gtsdude]

A lot depends on what you have for the rest of your combo, auto trans or 4 speed? if auto what stall converter? compression, vehicle weight etc. You can run all that stuff passed a cam grinder of your choice and they should be able to get you what you need and want in a cam.

 

[RustyRatRod]

A lot of times though, the heads can be cracked and you'll never have a problem.

 

[gtsdude]

A lot of times though, the heads can be cracked and you'll never have a problem.

X2, I wouldn't be afraid to run a set if they came off a running motor.

 

[FrostyMopar]

If you're thinking about swapping in a cam and you're also thinking that a set of high performance cylinder heads are an option.

I'd recommend do them both at the same time. They will work best if matched to one another.

Even if that means running your magnum motor "as is" until budget allows for cam+heads. or keeping the 318 in service until you've built the magnum the way you want it.

Stock heads would need to have the spring seats machined to take a higher lift cam. Plus there will be less performance gain than using the EQ heads since the stock ports probably peak at around .500" lift or less. spending money on something that you plan to replace in the future doesn't make much sense.

The EQ heads will still probably have to have the spring seats machined, as well as the valve job etc. But will flow way better numbers overall and realize peak flow at closer to .600" lift. better bang for your buck really. (if you've got the coin)

You mention using a crosswind intake. Is that LA intake bolt pattern or Magnum bolt pattern? To my knowledge they don't make a magnum version. That may be an issue.

If you don't mind getting creative, you can set up your cylinder heads to have BOTH intake manifold bolt patterns, or hughes engines will do it for you for about $90. still way cheaper than a new intake manifold.

Keep in mind the magnum will use a hydraulic roller cam and can be more aggressive than a solid flat tappet, allowing a much higher valve lift for any given .050" duration spec. The cam you listed doesn't appear very aggressive for a roller but would make for a quiet, super reliable valvetrain. A lot of "off the shelf" cams are made this way.

 

[jbc426]

These Magnums make for a nice swap. Oh, and , uhm...don't forget to use a 4 piece LA oil pan gasket on the pan. The one piece gasket only works on the stock Magnum pan. Learned that one the hard way.

 

[273]

If the scrap yard allows you to do a compression test that would be you best bet to check engines health.

As long as your engine has good compression it doesn't matter if the heads are cracked the heads are just not worth rebuilding if they are. And it's debatable if there worth if not cracked since EQ'S are cheap and offer more performance. I got a 5.9 jeep and the previous owner ovee heated the **** out it twice and I'm sure the heads are cracked never noticed a problem though.

And the main advantage of the magnum is to take a running engine and add cam,4bbl and headers and have 350-400 plus hp and up to 450 with heads. But if your gonna rebuild from day one any 360 will do.

 

[Walker434]

I'm running stock heads and a cam with similar specs. 230/234 @.50 .506/.513 lift. 106 cl 110 LSA. Air gap intake, Holley 750 DP and cheap headers. Ran 7.88 in the 1/8th first time out.

So I agree with doing a compression test in the junkyard. If that checks out i would run the stock heads. These magnums are stout with just the cam and carb swap. Good luck.