Thoughts on used Magnum heads.

[Mojoe9955]

I have a burnt exhaust valve on my 2000 Ram van. The exhaust manifold fasteners are so rusty they no longer resemble nuts or bolts. With that in mind I'm going to cut, grind or torch them to get the exhaust manifold off. Magnum heads are prone to cracking but, supposedly still work. I would have to have mine repaired at what cost? I have seen some used assembled head in good condition from eBay sellers with good feedback for around $250/300. I don't think my heads could be redone for that and I still have the exhaust manifold bolts/studs to deal with. If the seat looks good, I might be able to just replace the valve which I have from some old heads, lap it in with a new seal...

 

[SRT_DSTRHOLC]

I would say it depends on how much you want to save. They do/used to make the EQ heads and NOS magnums. I believe you have to get the heads checked as well a small surfacing, but your price range is about what I would expect for a tank,checking, and surfacing

 

[Mojoe9955]

I'm eliminating my previous ideas and am probably going with some reman heads. Any reviews on Chi or Allied Motors Cylinder heads?

 

[PRH]

Both of the two sets of well used magnum heads I’ve had my hands on had quite recessed exhaust seats and cracks between the valves in numerous chambers.

My suspicion is your heads will be in similar condition.

Depending on what machine shop costs are like in your area will probably dictate the best path forward(new, used, repaired).

It’s not unheard of that new import heads have had instances of valves sticking in the bores…….. so I wouldn’t advise them being used right ootb.

 

[SRT_DSTRHOLC]

I'm eliminating my previous ideas and am probably going with some reman heads. Any reviews on Chi or Allied Motors Cylinder heads?

I do not have experience with them directly. You could find some info in the threads on here that would be a good start. There is Brian from IMM that has his own machine shop and may have direct experience with them as well.

 

[Mojoe9955]

The van has145k on it, as much of a pain to get it apart, I'm thinking of doing both sides.

 

[RustyRatRod]

My thoughts are they're probably cracked.

 

[Mojoe9955]

I always forget about Rock Auto. Assembled Enginetech Heads, no core charge $601.79 a pair. Add on new head bolts, exhaust bolts and all new gaskets to do the job, plus shipping out the door and arriving Tues/Wed next week. $808

 

[PRH]

Fwiw, I’m on board with going with a pair of reman heads.

 

[remytherat]

I went through this a little over a year ago when I was looking for heads for my 5.9 build. What I found is that used heads are very rarely an option, because most of the heads out there are both cracked and have trashed exhaust seats. The cracks are supposedly fine, but exhaust valves that don't seal aren't in my book. Magnum seats are iron, and combined with lean running efi and a hard life in a truck, they don't survive too well. The machine shop I trust was very hesitant to try replacing exhaust valve seats on cracked heads.

I would just go with EQ (or equivalent) repop heads. Usually they have stellite seats and the casting is improved to prevent the typical cracking in the chambers. Have a machine shop go through them or buy them through a head remanufacturing company.

 

[junkyardhero]

The van has145k on it, as much of a pain to get it apart, I'm thinking of doing both sides.

in for a penny, in for a pound.

do it now, or you'll be doing it again in short order.

 

[RustyRatRod]

The cracks are supposedly fine, but exhaust valves that don't seal aren't in my book.

I don't agree with this popular assessment. Lemmie splain. You hammer on the reason in the above sentence. If a seat is cracked, it gives a "valley" on the seat. It will eventually lead to a valve that doesn't seat and or and burned valve. I JUST took the heads off the 351M that came out of my truck about three or so years ago. I pulled it because it was skipping on #5. A compression test before I pulled it revealed #5 with no compression. I removed that valve cover and both rockers so they would both be closed and applied compressed air to #5. Air rushing out of the tailpipe told me the exhaust valve was either not seating, or burned. When I removed the heads, I removed both valves from the #5 cylinder and found a crack running from the chamber right across the exhaust seat. Although the valve hadn't burned yet, you can see where the seat had failed. It's unfortunate, because I wanted to do another 400 since I was having so much trouble with the one that's in it now, but that seems to have been fixed.......I hope. lol So I cannot recommend running a head with a cracked seat. Also of note, there was no coolant loss and it held a pressure test overnight.

 

[RustyRatRod]

in for a penny, in for a pound.

Pound? Here's some for you. You know you want it.

 

[dogbreath]

I've used 2 sets of magnum heads from allied and both were fine no issues. They charged me an extra $100 core charge but they came with UPS prepaid shipping lablels for an easy return and $100 credit . I swapped the stock springs for the Hughes kit to run a .515" lift cam , no problems

 

[MOPAROFFICIAL]

I have a burnt exhaust valve on my 2000 Ram van. The exhaust manifold fasteners are so rusty they no longer resemble nuts or bolts. With that in mind I'm going to cut, grind or torch them to get the exhaust manifold off. Magnum heads are prone to cracking but, supposedly still work. I would have to have mine repaired at what cost? I have seen some used assembled head in good condition from eBay sellers with good feedback for around $250/300. I don't think my heads could be redone for that and I still have the exhaust manifold bolts/studs to deal with. If the seat looks good, I might be able to just replace the valve which I have from some old heads, lap it in with a new seal...

I wouldn't try lapping a new valve without grinding the seat. You can have a hardened seat put in if it's cracked on both sides, if you need to ,or just get a new head.

 

[junkyardhero]

I don't agree with this popular assessment. Lemmie splain. You hammer on the reason in the above sentence. If a seat is cracked, it gives a "valley" on the seat. It will eventually lead to a valve that doesn't seat and or and burned valve.

read again: cracked heads, not cracked seats.

magnums typically crack between the seats so a lot of machine shops are hesitant to install new seats, and a lot of reman houses give a very limited warranty on repaired units.

while typically it's fine as long as they're not pushing water, part of the problem is that the soft iron seats are usually hammered so the seal is crap.

and then you go back to step 1, where nobody wants to replace them so you're looking at new heads.

 

[RustyRatRod]

read again: cracked heads, not cracked seats.

magnums typically crack between the seats so a lot of machine shops are hesitant to install new seats, and a lot of reman houses give a very limited warranty on repaired units.

while typically it's fine as long as they're not pushing water, part of the problem is that the soft iron seats are usually hammered so the seal is crap.

and then you go back to step 1, where nobody wants to replace them so you're looking at new heads.

No you read again, dummy. I was talking about the cracked seats in MY head. Now get out my face. lol

 

[junkyardhero]

No you read again, dummy. I was talking about the cracked seats in MY head. Now get out my face. lol

go talk about your ferd on one of them blue oval forums rather than junk it up over here ya jerkus!

 

[RustyRatRod]

go talk about your ferd on one of them blue oval forums rather than junk it up over here ya jerkus!

I got it hangin and swangin for ya, buddy. Ha!

 

[Michael Harrington]

I always forget about Rock Auto. Assembled Enginetech Heads, no core charge $601.79 a pair. Add on new head bolts, exhaust bolts and all new gaskets to do the job, plus shipping out the door and arriving Tues/Wed next week. $808

Please report back on the condition/quality of those heads from Rock Auto.

 

[Michael Harrington]

I always forget about Rock Auto. Assembled Enginetech Heads, no core charge $601.79 a pair. Add on new head bolts, exhaust bolts and all new gaskets to do the job, plus shipping out the door and arriving Tues/Wed next week. $808

Did you receive these heads and get to look them over? As of 10-03 my machine shop is trying to find me usable magnum heads for my engine. The ones from my engine were BAD-300,000 highway miles. I'm not ready to spend over $2400 for Edelbrocks.

 

[Mojoe9955]

I actually got them from Allied Motor Parts in Georgia. I wrongly assumed that the Rock Auto price was for a pair of heads, when it was actually a single head, which is what I paid for a pair from Allied, $575+$75 shipped which had good and fair reviews according to FABO members. Mine had 145k on them and looked good inside other that a bad exhaust seat or valve. Outside with broken exhaust studs, rusted in spark plug tubes and a sparkplug that I broke trying to get the tubes out, a semi local shop quoted me "around $700" over the phone to rebuild them. Long story short, I, got the "new" heads yesterday, which looked good and are installed and hopefully I
should be back on the road later today or tomorrow.

 

[Michael Harrington]

I actually got them from Allied Motor Parts in Georgia. I wrongly assumed that the Rock Auto price was for a pair of heads, when it was actually a single head, which is what I paid for a pair from Allied, $575+$75 shipped which had good and fair reviews according to FABO members. Mine had 145k on them and looked good inside other that a bad exhaust seat or valve. Outside with broken exhaust studs, rusted in spark plug tubes and a sparkplug that I broke trying to get the tubes out, a semi local shop quoted me "around $700" over the phone to rebuild them. Long story short, I, got the "new" heads yesterday, which looked good and are installed and hopefully I
should be back on the road later today or tomorrow.

Thank you.

 

[PRH]

Give us a progress report/update after you've got some mileage on them.

 

[Slantsix64]

Please report back on the condition/quality of those heads from Rock Auto.

I purchased a rockauto reman head, I had a annoying valve train tick. I had to trim around the push rod pinch area because of casting flash with a carbide bit, due to push rods rubbing on the new reman head.

When I ported the reman head dear god the casting was so bad just to get it to look like a oem stock magnum head was some work! Only reason I bought a reman head was because the machine shop wouldn’t warranty the work. The other head oem head was not cracked.

If I could go back I would of just ran that oem head that had a crack. With no warranty.

Before this I pulled a set of magnum heads at the junk yard, slapped them on with no work done and yes they had cracks. The LA 318 would run constant 8.6-8.8 at the 1/8.
Never smoked never misfired nothing.

It’s all up to you in the end if you wanna take a gamble.