Edlebrock RPM Heads on Stock Engine Questions

rumblefish360

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I run a 400 block 451 in my 68 Sport Satellite with RPM heads fitted with big valves, RPM intake, 1.5:1 stock iron rockers, Mopar finned aluminum valve covers, and Schumacher Tri-Y headers. Stock distributor fits fine. My flat top pistons are .015" in the hole with .027" Cometic gaskets and clear just fine.

Remember that for these Eddy RPM aluminum heads, they take a different length plug that is longer than the requirement for the stock iron heads.
Almost all of what you wrote is not helpful since you did not include any cam information like duration and lift as well as what pistons your running that may or may not have a valve relief for clearance. The deck clearance (.015 in the hole with the head gasket of .027) is mostly helpful elsewhere and of minor use to the poster. Though it does help clue in your tight clearance to what ever super secret cam your running.

Regardless, your new bore and stroke as well as pistons are a vast change from a stock 400 B&S and piston depth.

Why did you post this again?
 

Geoff 2

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This sounds like another disaster in the making....
RPM heads, very large ports, going on a stock, low comp 400. Stock heads will perform much better in this application.
 

Kern Dog

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The Fel Pro Perma Torque gaskets are fine, despite what Edelbrock literature states. I've ran Edelbrock heads since 2004 with Fel Pro gaskets and have had zero trouble.
 

BSB67

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The Fel Pro Perma Torque gaskets are fine, despite what Edelbrock literature states. I've ran Edelbrock heads since 2004 with Fel Pro gaskets and have had zero trouble.
Yep. This too
 

Myasylum

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This sounds like another disaster in the making....
RPM heads, very large ports, going on a stock, low comp 400. Stock heads will perform much better in this application.
Well I'm hoping these heads will increase compression so that won't be an issue. Anyone else have thoughts on this?
 

66Satellite47

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The EDE RPM heads have somewhat larger ports, both intake and exhaust with a better port configuration. I don't see a problem there. The 75 CC version will give a bump in CR compared the OEM iron heads which were all at least 13 CC's larger. Do the math. The Cometic head gaskets have a great reputation, but the require a specific type of milled surface on the block and heads, which I'm 99% sure you don't have. I know I don't. Your choice of a cam and a corresponding torque convertor is what will MAKE the combination.
 

RemCharger

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Cometics are used daily on original deck surfaces.. not saying it's the perfect scenario. But better than wrecking the surface of an aluminum head with a stock shim gasket.
 

Kern Dog

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That recommendation for the surface finish may be another matter where the manufacturer is being cautious. I have used two sets of Cometic gaskets with regular machine work done to the block and heads. No leaks from what I recall.
Have I just been lucky ?
 

66Satellite47

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You guys would know more than I, since I've never used them. I just know what I saw as the manufacturers recommendation and several builders.
 

RemCharger

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No. You're just like everyone else.
Reply to Kern
 

BSB67

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Cometics are used daily on original deck surfaces.. not saying it's the perfect scenario. But better than wrecking the surface of an aluminum head with a stock shim gasket.
Never seen them wreck an aluminum head.
 

66Satellite47

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Guess I thought I did to both of you. I know what I don't know.
 

Curiousyellow71

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On this project I wouldn't try running a thinner head gasket...like a steel shim or cometic. The TINY hp gains aren't worth the risk of having to replace a leaking head gasket. I would run the fel pro 1009 gaskets mentioned or comparable.
 

Curiousyellow71

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That recommendation for the surface finish may be another matter where the manufacturer is being cautious. I have used two sets of Cometic gaskets with regular machine work done to the block and heads. No leaks from what I recall.
Have I just been lucky ?
Regular as in fresh or oem factory finish? We have been doing mirror finish on cometics ..but it does seem like it's overkill.

We reused a set of factory shims coated with copper coat on a 400. They smashed down to .015. Copper coat is good stuff though. Used on a few diesels over the years w reused head gaskets.
 

66Satellite47

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Regular as in fresh or oem factory finish? We have been doing mirror finish on cometics ..but it does seem like it's overkill.

We reused a set of factory shims coated with copper coat on a 400. They smashed down to .015. Copper coat is good stuff though. Used on a few diesels over the years w reused head gaskets.
So do you believe in the Cometic recommendations for the micro finish or not? You are a builder, I'm sure not.
I wonder if the steel shim gaskets would really be hard on aluminum heads with used with Kopper Kote as I always did with iron heads? You've obviously done a lot more motors than me.
 

Curiousyellow71

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OkSo do you believe in the Cometic recommendations for the micro finish or not? You are a builder, I'm sure not.
I wonder if the steel shim gaskets would really be hard on aluminum heads with used with Kopper Kote as I always did with iron heads? You've obviously done a lot more motors than me.
There really is nothing to seal up a slight imperfection w a cometic or a steel shim. So if either is assembled dry I think it's asking for trouble unless you really have a nice surface on the head and block...now if you coat it w copper coat?...have not tried it yet with a cometic. It has worked on the steel shim type. But cometic's are somewhat complicated compared to the oem shim. Probably hard to reuse again once copper coated. But Certainly I think there is more room for imperfections if you coat them.

If the op wanted to use a thinner shim or cometic I would coat the engine surface and not the head with copper kote. But...again I don't think that the little bit of compression is worth the risk if the block is not being decked.
 
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Myasylum

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I think after reading all this i'm probably better safe than sorry. Probably should stick with the recommended gaskets. Thanks!
 
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