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Discussion Starter · #4 ·
also what can i expect from 8.8:1 compression ? will i have to burn higher test gasoline ? and is that a good ratio , this is my first engine build as i am only 18 , just trying to get everything figured out here :D
 

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Sorry...was busy at my "honey do list" the fire ring OD (outside diameter) on the 1003 Fel Pro is 4.166", you have a 4.00" +.040 327 which makes it 4.040" so you have lots of room. If you really know your compression ratio is 8.6:1 then you will be fine to run 87-89 octane gas.

You can "usually" run up to 9.5:1 on the crappy street gas. There are numerous compression ratio calculators on the web, they will ask you about your engine specs to find your specific compression. Since you're new to this stuff I would strongly recommend you make sure what your engine compression is before running it on the street. You hear guys on here all the time saying...."oh it's about 9.5 to 1 compression" which in reality means they have no clue what the compression is because they either didn't REALLY build the engine or were too lazy to do the math. READ...READ...READ everything you can get your hands on, do it right the first time, good luck.
 

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soooo a stock 4 inch bore sbc gasket will work ?
The gasket bore diameter is published for every gasket. Most are around 4.09" to 4.1" that are made to work on a 4" nominal bore SBC. You want at least 0.030" between the fire ring and the bore. More room is not wanted if it can be avoided- it created a "dead area" that costs compression, causes more emissions and contributes nothing.
 

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Virtually all makes of "replacement" gaskets will fit up to an .080" over bore on the 4" Chevy. The Felpro Performance gasket mentioned is "nice", but hardly necessary for such a build. The "stock" type gaskets are fine. The "blue" Felpro are popular. The Victor/Reinz is excellent as well. Avoid those without a brand name... Once compression goes over 11:1, we start considering other gaskets.

FWIW

Jim
 
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