Using head gaskets to lower compression...

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sledger46

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Came across a great deal on a fresh rebuilt 360 short block with zero deck height. The problem I would have is my heads are iron EQ heads with 62cc chambers. Playing with the compression calculators online I would need a .060' thick compressed head gasket to get the compression down to 9.8. What sort of problems will I run into with using such thick gaskets?
 
It could make it worse. I am assuming it is built as a quench engine. Running a .060" thick gasket could lose the quench it has and make detonation a real problem. If you can give more specifics on the engine such as which pistons and cam it would help.
 
Looks like it is bored .030" over with forged SRP pistons with 5cc for valve reliefs. Initially I was planning on running my existing 224/230 cam with 110 LSA and .513" lift. I do have access to 93 octane unleaded.
 
With a .039 gasket I come up with 10.8. That would work with the quench and some more cam.
 
mopowers said:
Where are the pistons in the hole? At zero deck, I got 11.07 to 1 with a .039" gasket.
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I am being told it is zero deck. I hope to get to see it this weekend and bring my own straight edge and feeler gauge to check for sure. .020" in the hole would be sweet and result in a 10.43 compression ratio.
 
I believe you would still want some quench. Ideally, opening the chambers a tad would work well if that's an option, as opposed to widening the piston-quench pad distance.
 
Make sure the compression ratio calculator you use takes gasket bore into account. Some of them don't and there is an effect, albeit a slight one. Most of the felpros I've seen are 4.180" bore diameter.
 
mopowers said:
Make sure the compression ratio calculator you use takes gasket bore into account. Some of them don't and there is an effect, albeit a slight one. Most of the felpros I've seen are 4.180" bore diameter.
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The fel pros that I have measured from the mancini kits have 12.4 cc volume.
 
I used .027" thick cometic gaskets on my 318 with the EQ Heads. They were the thinnest I could find. My pistons are .060" down in the hole. If I recall my math brought it around to about 9.4 ish.
 
mopowers said:
I believe you would still want some quench. Ideally, opening the chambers a tad would work well if that's an option, as opposed to widening the piston-quench pad distance.
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X2. Open up the chambers then run the Fel pro gasket from the Mancini kit.
 
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