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building a 408 what compression will this setup be

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Old Apr 13, 2007 | 12:03 PM
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CamaroRick's Avatar
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Default building a 408 what compression will this setup be

I am in the process of building my 408. I ordered my rotating kit from ls1 speed

compstar forged 4"crank
compstar forged 6.125" rods
Diamond forged 4.030" bore -2cc dished pistons
clevite coated main and rod bearings

this is all going into my 6.0l iron block which will be bored 4.030
I will use the l92 heads and l76 intake

using the stock 68.9cc combustion chamber what will my compression be with a .052" compressed head gasket? i originally wanted to run a 10.5:1 compression with -10cc pistons , but ls1 speed advised me to go higher with the -2cc pistons saying ill be fine with 93 pump gas. will this work out?

whats the highest compression i can use on a good tune with 93?
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Old Apr 13, 2007 | 12:05 PM
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11.3 Static compression, should be fine on pump gas. What cam will you be running?

FWIW I run 11.9 on 93 octane
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Old Apr 13, 2007 | 12:49 PM
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I dont have one yet, i was going to talk to my head porter on a reccommendation Im looking for a some what agressive cam
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Old Apr 13, 2007 | 07:12 PM
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Default 10.7 SCR for me!

The guy doing the L92 heads for me recommended 10.7 SCR for my 402.

His reasoning was that if I went to 11.5 I couldn't run as much timing. This guy builds some nasty motors.

I'll see in a week or two.

Bob K.
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Old Apr 15, 2007 | 11:29 PM
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Bob, what camshaft are you going with? It seems that no one really knows what cams seem to work good with these heads due to the offset valve. I wonder if GM's 239/251 .570"/.570" 106.5 lsa would work. My car doesn't need to be show room streetable, as long as it idles and pulls like hell up top (Even if I have to make peak HP over 6500). How high are you planning on reving?
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