Head gasket for magnum block and la head

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1bad360duster

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I am going to be using aluminum la style heads on a magnum block but will be oiling through rockers so that’s a non issue as far as oil holes go. No reason otherwise I cannot run a la style cometic gasket on the magnum block correct? Just checking before I order. Thanks
 
C5633-040 is what I want to use, this is a high compression deal so want to use the cometics
 
It should be fine. We've used Felpro 8553 Perma Torque LA head gaskets on magnum engines without any issues.
This is just for an example, but the only problems I have see have been magnum gaskets on an LA. This is a Felpro 540SD magnum head gasket and the pushrod holes in the gasket do not line up with the pushrod holes (about half off to the inside) in iron 360 heads but are very close to aligning with the pushrod holes in a 318 LA head. An arbor press type sheet metal pin punch could enlarge the holes without issues. But if you notice, it has the oil holes for LA rocker shaft oiling. But in your case, you should be okay with LA head gaskets whether oiling through the head or through the pushrods as long as you get the bore size reasonably close.
fel-540sd_xl.jpg
 
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You did not specify if you are running cast iron aluminum heads. There are different coolant passages in the different Cometic part numbers and they are based on which head you are planning to run.
Magnum block and LA block can be treated the same, just order correct gasket for the head.
@pittsburghracer previously mentioned ordering his Cometic gaskets through 4secondsflat.com and they help make sure the correct style is selected. That is how I plan to order my next set.
 
Garrett Ellison said:
It should be fine. We've used Felpro 8553 Perma Torque LA head gaskets on magnum engines without any issues.
This is just for an example, but the only problems I have see have been magnum gaskets on an LA. This is a Felpro 540SD magnum head gasket and the pushrod holes in the gasket do not line up with the pushrod holes (about half off to the inside) in iron 360 heads but are very close to aligning with the pushrod holes in a 318 LA head. An arbor press type sheet metal pin punch could enlarge the holes without issues. But if you notice, it has the oil holes for LA rocker shaft oiling. But in your case, you should be okay with LA head gaskets whether oiling through the head or through the pushrods as long as you get the bore size reasonably close.
View attachment 1715858977
Click to expand...
I cut the portion of push rod holes off.
Is there any diff between the 519,521,540 sd's...if at all the oil hole for shaft rockers and the push rod holes..?
They are .054 thick when compressed
 
Bobzilla said:
You did not specify if you are running cast iron aluminum heads. There are different coolant passages in the different Cometic part numbers and they are based on which head you are planning to run.
Magnum block and LA block can be treated the same, just order correct gasket for the head.
@pittsburghracer previously mentioned ordering his Cometic gaskets through 4secondsflat.com and they help make sure the correct style is selected. That is how I plan to order my next set.
Click to expand...


I’ll be calling for a set for my 422 soon because of long wait times.
 
Well I ordered the c5633-040 la gasket. I’m planning to run aluminum promaxx castings.
 
1bad360duster said:
Do you recall what part number you usually run. I ordered c5633-040 for la 360
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In the house for the night but I will try to look tomorrow. When Don orders them I’m not sure they even have a part number as they are custom. Pretty sure he sizes them .030 over bore size but that I will have to check too to be sure.
 
And that one links to this one:
ALERT!! SOUND THE ALARM!!..

Pittsburgh racer has a completely different part number I think because it was custom ordered, not a shelf number. But his gaskets are shown in post 877.
@TurboGLH used C5622 according to post 894.
 
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Thanks for
Bobzilla said:
And that one links to this one:
ALERT!! SOUND THE ALARM!!..

Pittsburgh racer has a completely different part number I think because it was custom ordered, not a shelf number. But his gaskets are shown in post 877.
@TurboGLH used C5622 according to post 894.
Click to expand...
Thanks for the links, but now I’m more confused lol. I guess if your running la heads on magnum block la gaskets should be the way to go but looks like some water passage shape differences
 
Forget the Magnum block. Just make sure the gasket matches the head. Cometic has a number suggested for stock cast iron LA heads, and a different one for Edelbrock Aluminum heads (and all copies like Promaxx and Speedmaster). I think there was another number for Magnum specific heads, but the block is basically the same as an LA.
Pretty sure some of us are running whatever was in stock and they still work.
 
Bobzilla said:
Forget the Magnum block. Just make sure the gasket matches the head. Cometic has a number suggested for stock cast iron LA heads, and a different one for Edelbrock Aluminum heads (and all copies like Promaxx and Speedmaster). I think there was another number for Magnum specific heads, but the block is basically the same as an LA.
Pretty sure some of us are running whatever was in stock and they still work.
Click to expand...
I think the consensus is I’m overthinking it lol. I did order the standard la c5633 but promaxx recommend a felpro that is a standard la as well.
 
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