Need some advice on some cylinder head gaskets

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naji408

naji408

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So, I have a 408 ci Magnum block with eddy rpm heads, and at NA I’m probably close to 10:1 CR.

Im currently setting up a twin turbo system with the Pro-Flow 4.

I’m pulling off the heads to drill the LA pattern for the intake.

Question is, are there any on the shelf head gaskets that you guys would recommend? Everything I see has such a large bore, which I don’t know if that is ok. I also want to go as thick as possible to lower the CR.

My current bore is 4.030, and I plan on running it at 10 psi. It will never exceed 15 psi, the edelbrock computer will shut it down (I think) if it exceeds that.

Today I finished mocking up my intercooler pipes, so please don’t mind me for showing off with a pic lol

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Garrett Ellison said:
Which pistons and how far are they below deck?
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They’re Icon Premium Forged. I couldn’t tell you how far below they are. It’s been a while since the motor was put together.

There seems to be a lot more options for the LA type gasket. I’m pretty sure they would work also. Just biggest concern is the bore size on the gaskets.
 
O-ring the block and run a high quality copper head gasket.
 
naji408 said:
something I should have done while building it a decade ago. Not something I want to do now.
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There's no other real way to guarantee not having a blown head gasket then. I suppose Cometic would be your next best bet.
 
naji408 said:
I hear you. Just wondering if anyone’s had success with any of the Fel-Pro’s
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Oh I'm sure. That's my next suggestion. The good old FelPro blues. They'll probably hold up pretty well.
 
naji408 said:
But with the bore size being .150 larger, am I asking for trouble?
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I don't understand how. That's .075" per side. Stack it up on a feeler gauge and see. It ain't much.
 
MOPAROFFICIAL said:
Water injection?
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Air. I have it tucked between radiator and grille and bumper. I’ll post pics when completed. I haven’t been this motivated since restoring it a decade ago.

this was the pic before I changed the inlet placements. I now have them on top, with the outlet on bottom.

had to chop a bunch on my baby

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How much quench are you gonna have running a thick head gasket to lower your compression ! You get to much quench you may run into a detonation problem, could tear up some pistons !!
 
Rmoore said:
How much quench are you gonna have running a thick head gasket to lower your compression ! You get to much quench you may run into a detonation problem, could tear up some pistons !!
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I plan on checking that when I have the head off. No idea on the top of my head.
 
naji408 said:
But with the bore size being .150 larger, am I asking for trouble?
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No. But it would be advantageous to have the least amount of wasted space. Cometic gaskets….

Rmoore said:
How much quench are you gonna have running a thick head gasket to lower your compression ! You get to much quench you may run into a detonation problem, could tear up some pistons !!
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Negative Sir. Timing is more of the issue at hand, not quench. He could run a flat top zero deck piston with a .030 head gasket at .010 more bore size than the cylinder and a closed 63cc head while adding boost.

Now the amount of boost could be limited due to timing limitations. If the timing could be taylored correctly, he could still run 15 lbs. of boost.

At this point of running boost, I, myself, would run a forged slug.
 
What fuel?
10psi intercooled with aluminum heads at 10:1, port injection…you could run 91 octane. 1008 head gaskets will do the job just fine.
 
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What turbos? Turbine housings look pretty small.
 
Ok, so searching, and searching, I see two options that may work. A copper 4.060 bore, with a .093 thickness that doesn’t need the block or head to be o-ringed. Or, if I can find the answer if they are MLS gaskets, the 519sd fel pro permatorque severe duty.
 
turbovan said:
What fuel?
10psi intercooled with aluminum heads at 10:1, port injection…you could run 91 octane. 1008 head gaskets will do the job just fine.
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I think I’m over thinking the whole thickness of the gasket thing to lower cr. Here in the Silicone Valley, it’s really hard to find higher octane fuel.
 
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