O-ring or Fire ring???
O-ringing the head is most common for steet trucks and will hold for twins, fire ring is for the extreme sled pullers making crazy boost i would go with some ARP 12mm studs and get your head o-ringed for around $300
A local shop (PDI) does fire rings, but not o-rings. Jetpilot (PDW) said in his opinion that fire rings aren't as streetable as o-rings. I drive my truck everyday (100-150 miles) and I don't want something that is going to fail like my stock HG did. What do the masses think?
when you do fire rings you have to cut the metal fire ring (metal ring around each cylinder) out of the headgasket because it is replaced by the ring thats placed in the head and block. o-rings leave the fire ring in the headgasket, and just use a small ring around the cylinder to apply extra pressure down on that ring to seal it tighter
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"O ring" is a .041 stainless wire (or similiar) pressed into a groove cut into the head. The wire has 10 to 15 thou protrusion and it presses into the factory fire ring in the factory gasket.
A "fire ring" is a welded annealed .105 ring that is placed into a larger groove that is cut into the head. It seals against the block. The factory fire ring in the gasket is cut out and the "annealed ring" is left to do all the combustion pressure sealing.
Both systems will NEED head studs properly maintained and torqued!!!
I have used fire rings in the past with good success, but to do it over again I will o-ring the head. I have a pile of factory gaskets. The fire ring head gaskets are expensive.
Both systems can be placed in the head or the block or both. Choose how much work you want to tackle...
Here is a picture of what fire rings look like getting ready to be placed on the block.

One thing I know for certain is the quality of machine work is imperative to get right.
A "fire ring" is a welded annealed .105 ring that is placed into a larger groove that is cut into the head. It seals against the block. The factory fire ring in the gasket is cut out and the "annealed ring" is left to do all the combustion pressure sealing.
Both systems will NEED head studs properly maintained and torqued!!!
I have used fire rings in the past with good success, but to do it over again I will o-ring the head. I have a pile of factory gaskets. The fire ring head gaskets are expensive.
Both systems can be placed in the head or the block or both. Choose how much work you want to tackle...
Here is a picture of what fire rings look like getting ready to be placed on the block.

One thing I know for certain is the quality of machine work is imperative to get right.
Agree with all Justin says above. I have had Firerings (head only) since Jan,2004... with no problems at 65 psi for the last yr. At the time, they were the latest & greatest. Many had problems with them early on... but i believe most were due to less than careful attention paid to cutting the groove. Same has been true with O-Rings.
The firering gaskets are very stout... but as Justin says, not cheap. I would not want to substitute factory gaskets on a fireringed head. How they compare to marine gaskets or other choices, I'm not familiar enough to say.
I have often heard that o-rings are more streetable but I don't know why this would be true. This statement usually applies to the copper Firerings but they come in steel also. I've had no trouble and I too drive my truck everyday.... but I am **** about checking head pressures (TIP or drive pressure) any time a change my setup!
If prices are in line, I feel picking a local shop that does good work is the most important thing.... be it O-ring of Firering.
RJ
The firering gaskets are very stout... but as Justin says, not cheap. I would not want to substitute factory gaskets on a fireringed head. How they compare to marine gaskets or other choices, I'm not familiar enough to say.
I have often heard that o-rings are more streetable but I don't know why this would be true. This statement usually applies to the copper Firerings but they come in steel also. I've had no trouble and I too drive my truck everyday.... but I am **** about checking head pressures (TIP or drive pressure) any time a change my setup!
If prices are in line, I feel picking a local shop that does good work is the most important thing.... be it O-ring of Firering.
RJ
Thanks for the reply's, I've learned a lot. I dropped my head off today to get Fire rings installed (that's all they do) the owner of the shop says he's got 40 or so trucks running around with this head setup with no problems. He also told me that he does the same setup whether you're drag racing, sled pulling, heavy towing, or just street performance. Anyways, at least now I can put my twins on without worrying about how much bosst it makes! Thanks again
DH
DH
PDI or http://www.performancedieselinc.com/. They are in ST. George, UT. Southwest corner of the state.


