Head gasket question

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B3422w5

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Have a forged flattop shortblock 340 +40( 418)
Pistons stick about 5 out of the hole.
Would an 039 be safe to run, or not enough room
Trying to not spring for cometics if i dont have to, and havent seen any others that are thicker than the 1008’s
 
Have you checked your piston to valve clearance yet. That would be the first thing I would do to tell "if" the 1008 gaskets will work.
 
cometic gaskets will give you both gasket thickness you need and a piece of mind. I would think your compression ratio is quite High another good reason to go with a steel shim style gasket. I have been using cometic gaskets for about 7 years now without one failure. I will never go back to Conventional gaskets. Yes they're expensive but what is your time worth pulling the top end of your motor apart and replacing gaskets
 
You're going to run a closed chamber head IIRC? I've known of guys that have ran closer than .034" piston to head clearance without issues and I wouldn't be afraid to try it with steel rods. As you well know check the piston to valve clearance. :thumbsup:

I'm thinking the original Fel Pro blue gasket was around .052-.054" compressed.
 
justinp61 said:
You're going to run a closed chamber head IIRC? I've known of guys that have ran closer than .034" piston to head clearance without issues and I wouldn't be afraid to try it with steel rods. As you well know check the piston to valve clearance. :thumbsup:

I'm thinking the original Fel Pro blue gasket was around .052-.054" compressed.
Click to expand...

justin, are you talking the blue felpro 1008. Isnt it 039 compressed, or is there another one
 
Fel pro 8553... If you buy the Edelbrock recommended gasket it's a felpro 8553 with Edelbrock packaging and you can pay almost twice as much....
Last I heard cometic was 8 to 10 weeks behind....
 
Last time I measured a compressed blue Fel-Pro gasket I believe it came in a little over 00.40
 
B3422w5 said:
this is the stroker kit i have. Unable to find the actual valve pocket depth, but they are sizeable.
Scat 1-48013 SB Chrysler 340\/416 Competition Rotating Assembly - 11.3:1 Icon Flat Top Pistons
Click to expand...
20141120_125419 (1).jpg

Probably the same icon Pistons I have. They have a very generous opening...
 
On my 367, I have run Q as tight as .028 with alloy heads, no contact/no problem. That was a firecracker out the dual 3" pipes at 11.3Scr and 180psi.
But on the inspection teardown, at the end of the summer, I found those .028 fire-rings migrating into the valley.
So I re-engineered for the FelPro .039s, and Q is now .034 and those FPs are taking 180psi just fine.
This is a cast crank 360 with bushed 340 rods and KB107 hypers under OOTB Eddies. Skirt clearance is generous at least 2.5thou. I'd like to be more accurate but assembly was in year 2000, and I just don't recall anymore. I remember taking it apart and opening it up because the engine would tighten up every time I shut it off. So I had the machine shop add a thou, to whatever it was, and I increased the top gap. which solved it. And bonus the engine ran cooler. But it rattled just a lil on cold mornings for just a few seconds. So then, afterwards I increased the minimum running temp to a tic over 200,lol, no problem.
 
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B3422w5 said:
Have a forged flattop shortblock 340 +40( 418)
Pistons stick about 5 out of the hole.
Would an 039 be safe to run, or not enough room
Trying to not spring for cometics if i dont have to, and havent seen any others that are thicker than the 1008’s
Click to expand...
My current motor has the pistons 5 thousands out of the hole, and I use the Felpro 1008....its snug (57cc Edelbrock heads), but everything seems to work OK. PV is also quite close, but works. Motor has been running for almost 2 years....so far, so good.
 
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