MLS Cometic Vs Felpro 1009 with Aluminum Heads

[Road Grabber]

Since I purchased Trickflow heads I have seen posts about MLS head gaskets working "better" than the Felpro 1009 gaskets. I did call Trickflow ahead of time before engine work and they said the 1009 gasket should work fine. Trickflow even lists the 1009 in the parts needed for assembly.

Now I have read the MLS gaskets are better when using the aluminum heads next to the cast iron block and but the block needs to be smooth for the MLS gaskets to seal properly.

What I don't know is how would I have checked the surface to see if it was smooth enough to use the MLS gaskets? Would you only use the MLS gaskets if the block was decked?

This is a 1968 440 block. Never decked bored .030.

If it was your block, would it be worth removing the heads to swap with MLS Cometic gaskets?

Felpro makes MLS gaskets but not for the 440. They claim their Permatorque gaskets are more forgiving with rougher block surfaces.

 

[toolmanmike]

Since I purchased Trickflow heads I have seen posts about MLS head gaskets working "better" than the Felpro 1009 gaskets. I did call Trickflow ahead of time before engine work and they said the 1009 gasket should work fine. Trickflow even lists the 1009 in the parts needed for assembly.

Now I have read the MLS gaskets are better when using the aluminum heads next to the cast iron block and but the block needs to be smooth for the MLS gaskets to seal properly.

What I don't know is how would I have checked the surface to see if it was smooth enough to use the MLS gaskets? Would you only use the MLS gaskets if the block was decked?

This is a 1968 440 block. Never decked bored .030.

If it was your block, would it be worth removing the heads to swap with MLS Cometic gaskets?

Felpro makes MLS gaskets but not for the 440. They claim their Permatorque gaskets are more forgiving with rougher block surfaces.

If it's not been decked I would used the Fel Pro's as recommended.

 

[69Bee]

With an undecked block, use the Fel-Pro 1009's as suggested. Cometic MLS head gaskets require a flat and smooth finish to seal. The problems usually show up when cold as the gasket rubber contracts and creates leak paths but seal up when hot. The Fel-Pro gaskets have a pre-flattened SS wire to seal the chamber and will leave a slight impression which is okay. I highly recommend to also use ARP head bolts or studs as the OEM bolts will chew up the bolt boss on the aluminum heads as they only have a narrow flat area under the head. The ARP bolts/studs will use a hardened washer that will distribute the clamp force better. Be sure to use the provided ARP Assy Lube, and not oil and pay attention to the ARP installation instructions.

 

[Road Grabber]

Thanks for the replies. I know some have had more experience with changing things up a bit and wanted to hear some feedback.

I’ll stick with the 1009s. Had Trickflow recommended the MLS gaskets when I called them I would have had the block decked by the shop at the start.

 

[lewtot184]

Unless something has drastically changed with the 1009 gasket they're the kiss of death on a big bore. Use a 8519, or 1039, or the marine gasket. I don't give a damn what trick flow, edelbrock or any body else says

 

[pnora]

Just make sure the 1009 fire ring does not hang into the combustion chamber. Sometimes the cylinder champher is a bit large and the ring can hang into it.

 

[PurpleBeeper]

Sorry to hijack.....I'm in this same situation. My block was decked 40 yrs ago (engine in the car now & due for a valve job) Would it be smooth enough for Cometics or were block deck finish specifications different back then?

 

[gkent]

A 40-year old deck job will use a gasket of that era - NOT an MLS gasket.

 

[gkent]

I don't give a damn what trick flow, edelbrock or any body else says

Well I personally am very glad that an expert has chimed in !!!

 

[Road Grabber]

Unless something has drastically changed with the 1009 gasket they're the kiss of death on a big bore. Use a 8519, or 1039, or the marine gasket. I don't give a damn what trick flow, edelbrock or any body else says

I have used the 1009 on my 440 and 383 with cast iron heads with no issues. This is my first rodeo with aluminum heads.

Are those other gaskets composite?
I’m not familiar with the marine head gasket. Can you please explain the difference?

This engine by the way produces 200 psi compression.

 

[Road Grabber]

Just make sure the 1009 fire ring does not hang into the combustion chamber. Sometimes the cylinder champher is a bit large and the ring can hang into it.

This cylinder does not have a chamfer that I have heard the newer blocks have. I have had the heads off once before and the “witness” marks from the ring are outside the closed chamber.
Thanks

 

[Road Grabber]

Sorry to hijack.....I'm in this same situation. My block was decked 40 yrs ago (engine in the car now & due for a valve job) Would it be smooth enough for Cometics or were block deck finish specifications different back then?

No worries. I want to hear it all.

 

[Road Grabber]

Just make sure the 1009 fire ring does not hang into the combustion chamber. Sometimes the cylinder champher is a bit large and the ring can hang into it.

Yes I have heard of that problem. No chamfer at the top of my cylinders. Thanks

I’m interested in knowing about longevity if they do work in the beginning but don’t last with the aluminum heads.

 

[Road Grabber]

Unless something has drastically changed with the 1009 gasket they're the kiss of death on a big bore. Use a 8519, or 1039, or the marine gasket. I don't give a damn what trick flow, edelbrock or any body else says

Who makes those gaskets? Felpro?
Do you have to order them according to bore size?

 

[BSB67]

Well I personally am very glad that an expert has chimed in !!!

He’s just speaking from experience. The 1009s fail with aftermarket aluminum heads from time to time despite the manufacturer’s recommendation.

 

[pnora]

Yes I have heard of that problem. No chamfer at the top of my cylinders. Thanks

I’m interested in knowing about longevity if they do work in the beginning but don’t last with the aluminum heads.

Lay the 1009 on your block. If the fire ring is out of cylinders champher you will be fine with them. Torque to specs and after some run time retorque them to be sure.

 

[69Bee]

Sorry to hijack.....I'm in this same situation. My block was decked 40 yrs ago (engine in the car now & due for a valve job) Would it be smooth enough for Cometics or were block deck finish specifications different back then?

Different back then. Carbide cutters were used normally on a "Pie" shaped surfacer; 85B from Storm Vulcan. The surfacers of today use CBN for cast iron, and PCD for aluminum. The speed and feed are manipulated to get the desired surface finish. The only caviet is if the block was ground, then it could be smooth enough. Rudimentary check, draw your fingernail across the surface (perpendicular to the swirl pattern) and if it is rough kind of like a file, it is too course for MLS.

 

[gkent]

OP ... how thick of a gasket do you need ??

 

[pnora]

He’s just speaking from experience. The 1009s fail with aftermarket aluminum heads from time to time despite the manufacturer’s recommendation.

We ran them on aluminum heads 12.5 compression. No problems. Easy to blame a head gasket for being the failure. My experience is a gasket fails for a reason. Most of the time you will never get the full story.

 

[Road Grabber]

We ran them on aluminum heads 12.5 compression. No problems. Easy to blame a head gasket for being the failure. My experience is a gasket fails for a reason. Most of the time you will never get the full story.

Thanks for the replies and advice. I do plan to retorque the head bolts.

Curious though. What is the difference and or reason why the marine head gasket may be better? Is this tried and proven?

If there is a problem in the future I would like to know.