OEM heads

[Yeret]

So, my old man and I have been talking about engines in general and I brought up my 5.9. Over the course of discussion, I remembered reading a while back that the factory heads on these engines were kinda cheesy and prone to cracking. My question is are these heads as bad as a lot of people say they are? And if so, where were they most prone to crack? And if one were to rebuild their engine (as a daily driver where reliability is more important than performance) and needed a new set of heads, what would be a good route to go?

Thanks in advance for all input.

 

[rowdyram]

They most often crack between the valves from what I've seen but have seen 1 or 2 crack elsewhere. That said a lot of heads crack here and are still serviceable. Aluminum head rebuilders here in Oregon and cylinder heads Intl. Are 2 places I've used and had 100% success. I think cyl heads Intl is second in quality but you can get a rebuilt head for about $150 and one set I put on now has over 65k with no problems.

 

[MoparMagic'00]

side note I've been told that the heads from the 5.2 and the 5.9 are the same heads.. valve sizes and all.. true or false?

 

[themoparkid]

5.2/5.9 heads are the same. Its just in the block that's different. Even though the heads are prone to cracking and most claim its a bad casting from Chrysler. A lot has to do with the motor not running cool. Faulty temp sensors or lack of coolant flush when necessary. Lack of coolant flushes = clogged radiator then comes over heating.

 

[rowdyram]

The 5.2/5.9 heads are mostly the same (though Chrysler made a ton if small changes) but there are some different ones the best flowing and most desirable are 88-92 5.2 heads with a casting # 308

 

[themoparkid]

The 5.2/5.9 heads are mostly the same (though Chrysler made a ton if small changes) but there are some different ones the best flowing and most desirable are 88-92 5.2 heads with a casting # 308

Can't use LA head's on Magnum blocks.

 

[rowdyram]

Well I guess I should have done more research before I opened my big mouth huh?

 

[Yeret]

Anyone have any input on Hughes' Iron Ram heads? Fully assembled stock replacements with 1.92 intake valves go for a grand (I remember them being around 850. Must've gone up, damn LOL).

However, if one were to swap in an entry level camshaft (thinking along the lines of Hughes HER0814AL grind) would it be worth the extra $400 to go with 2.02 valves? This is assuming one also adds a larger throttle body and keggar mod or a different manifold altogether (and a tune of course).

 

[BBartow]

Check out Odessa/Clearwater heads. Very popular and for a great price.

 

[rowdyram]

I dont have any experience with the iron rams but heard a lot if good things.

I think if your just looking for a reliable DD stock heads will be fine with that cam. I know its hard to keep it mild talking replacement parts but a stock build with that cam and a tuner will likely be all you need.

 

[dodge dude94]

Most heads crack due to heat, yes, but it's not from overheating it's from a clogged cat. If a truck has a hollowed out cat when you bought it, there is a good chance that the chamber on cylinder 8 is cracked.


Iron Ram heads are the best iron head out there for these engines, I personally wouldn't use stock heads for anything more than bolt ons due to the high probability of cracking them.

 

[Yeret]

LOL, the more I hear about plugged catalytics causing problems, the more distraught I become about mine plugging up a while back. I had to drive the truck several miles home when it happened then several miles to a mechanic who ended up ditching me for whatever reason (thanks for a phone call saying you can't'/won't do the job...) then had to drive several miles again to someone who would do the job. Now I have a ticking sound coming from somewhere in the engine under load (particularly in overdrive). Blown exhaust manifold gasket perhaps? I know that can cause a list of other problems.

******* catalytic converters...

 

[themoparkid]

Most heads crack due to heat, yes, but it's not from overheating it's from a clogged cat. If a truck has a hollowed out cat when you bought it, there is a good chance that the chamber on cylinder 8 is cracked.

How so?

 

[Merc225hp]

No cats ever, jugs 1-7-2-8 all had cracked valve seats, comp was down to 120 on these jugs. Jug #8 is the most commun jug to go down, thats why you see me post comp test starting with jug #8. Stock heads have poor coolant flow, stock heads are cast thin. Over torquing the intake bolts on these motors might also cause heads to crack. R/T heads are a better casting, have better coolant flow, but try and find a good set. I see no reason to go big valve on a truck motor, unless it's stroked and you plan on being above 4000rpm most of the time.

As for repairing these heads unless you do all 8 it is a waste of time and by the time you fix 8 for what that cost you can get new thick cast heads.