Best headgasket for modified 305 build?
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Best headgasket for modified 305 build?
Hey there guys, been around on the forums for a longg time now and im working on another 305 motor for my new 86 z28 that I have. Ive got a few questions about which headgasket to use on my 305 build that im doing. Looking for some technical data, as most of the 305 gaskets ive found dont list a bore diameter or compressed thickness in their descriptions?
The only 305 application headgasket ive found with the data I need is the mr.gasket one #5780G which is a .028 compressed thickness with a 3.87 bore diameter. My problem is most of the performance (thin) headgaskets ive found are all a 4.1xx bore which I know is too big. I have the block decked so the piston is .012 in the hole and the heads are milled to a 52cc. Im trying to keep quench tight on the motor, thats why im concerned on the gaskets. Has anyone used the felpro #8510PT? What is the diameter and thickness of that gasket? What do you recomend?
The only 305 application headgasket ive found with the data I need is the mr.gasket one #5780G which is a .028 compressed thickness with a 3.87 bore diameter. My problem is most of the performance (thin) headgaskets ive found are all a 4.1xx bore which I know is too big. I have the block decked so the piston is .012 in the hole and the heads are milled to a 52cc. Im trying to keep quench tight on the motor, thats why im concerned on the gaskets. Has anyone used the felpro #8510PT? What is the diameter and thickness of that gasket? What do you recomend?
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
If the pistons are .012" down in the hole, the .028" compressed gasket would be perfect.
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Re: Best headgasket for modified 305 build?
Im sorry I actually just re-read what I wrote and realized I mis-typed it. I was at work and in a hurry when I wrote this up. My piston is .010 in the hole. And I also did a little more reading on the #8510PT felpro gasket, its looking like those are .039 compressed thickness. They are aso more readily available. Which should I go with? Was hoping some of the old 305 guru's (mw66nova, FAST355) would chime in....
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Re: Best headgasket for modified 305 build?
the last gaskets i used before going lsx was a steel shim head gasket. had a 4.1" bore if i remember correctly. it was like .016" maybe. if you can find a .028" gasket i'd imagine you'd be OK even if the bore is a little big. the motor is actually still together with no signs of detonation, even at 10.5:1 with iron heads and 40* locked out timing. run 93 octane and it should be a-ok
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