LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Head gaskets for 13.5+ compression?

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Old Feb 18, 2013 | 08:49 AM
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Default Head gaskets for 13.5+ compression?

I'm ordering my parts for my 13.5+ cr 383/388 build and I have a few questions before ordering parts. I am debating whether or not I would need MLS gaskets for that much compression or if the .026 Mr.Gasket would be ok. I am aiming for around .030 quench as well.
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Old Feb 18, 2013 | 09:14 AM
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I've had great luck with Mr Gasket MLS headgaskets, but I think they're .039 ot .040. Have you ordered pistons and rods yet? Block machined yet? Just hang the piston out.
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Old Feb 18, 2013 | 10:04 AM
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I have 6" rods, have a stock (unmachined) 4-bolt block, was going to order crank and rods today. I was thinking of 1 of 2 options.

1) 3.80" stroke with 1.125 piston, deck .015 (assuming standard .025 currently), leaving .030 quench with a .040" gasket.
2) 3.75" stroke 1.125" piston, deck to 9.005 with .026" gasket leaving .031 quench.

Block will be machined and shortblock assembled by the shop.

Last edited by kgkern01; Feb 18, 2013 at 10:10 AM.
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Old Feb 18, 2013 | 10:45 AM
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Cometic will make you pretty much any gasket you want at any thickness and for any compression.

They are pricey though!
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Old Feb 18, 2013 | 01:00 PM
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Yeah custom gaskets are expensive, but if I can use the .040 gasket with .005-010 "out of the hole" to get good quench that may be the route to go to save some $ while still "doing it right".
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Old Feb 19, 2013 | 12:36 PM
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Originally Posted by Wicked94Z
I've had great luck with Mr Gasket MLS headgaskets.
I regularly push 12 lbs of boost into my 383 using Mr. Gasket MLS head gaskets; at the stock C/R too, so they'll hold 13.5 to 1 just fine!

: )
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Old Feb 19, 2013 | 02:01 PM
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cometic ftmfw....i ran a non mls gasket at 13.2:1......it doesn't end well lol......i run cometics now at 14.5:1 with no issues at all......as for quench unless you got some strong *** steel rods and a perfect tune do NOT go under .030 quench
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Old Feb 19, 2013 | 03:41 PM
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Yeah after doing a little more online 'research' I've decided on a .35-.40 quench, I don't think the risk is worth the rewards there.

Side question, what about a tiny flat dome (.10 or less) to get an extra point compression vs staying flat-top and 13.5 cr?
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Old Feb 19, 2013 | 03:57 PM
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Originally Posted by kgkern01
Yeah after doing a little more online 'research' I've decided on a .35-.40 quench, I don't think the risk is worth the rewards there.

Side question, what about a tiny flat dome (.10 or less) to get an extra point compression vs staying flat-top and 13.5 cr?
what about it? lol if ur asking if its ok yes domes are fine just be prepared to run good fuel
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Old Feb 19, 2013 | 05:40 PM
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I never had a GM B body LT1 head gasket fail with 14.25-1. Good fuel and tuned correctly. I would not try to run less than .033" with steel rods. Closer and you will likely touch the pistons to the heads which upsets ring seal at TDC. That cost power. Lots of power with good ring seal. Hit the heads hard can pinch rings. .035" is safe and will make the same power as .032" or .033".
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Old Feb 19, 2013 | 06:07 PM
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Originally Posted by quik95lt1
what about it? lol if ur asking if its ok yes domes are fine just be prepared to run good fuel
Yeah it's a strictly E85 build, which is why I'm trying to maximize compression to get the most out of it. That's why I was asking if it was worth it to go with small flat dome pistons for ~14.5 vs flat top for 13.5 on E85, as I have heard that flat tops produce a better flame?
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Old Feb 19, 2013 | 06:27 PM
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I don't think a small dome like you are talking about will hurt flame travel that much. You could always clearance the dome some in the plug area if you're really worried about it.
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Old Feb 19, 2013 | 07:19 PM
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It amazes me how many are willing to run that nasty, corrosive crap through their engines.
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Old Feb 19, 2013 | 07:51 PM
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I've been running it for 6 years in my heads/cam car. It's approx 105 octane, resistant to detonation, and keeps the fuel system clean. I have no signs of corrosion in my fuel system from it. I know a few others here are having good results with it...
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