C/R ratio

viper3508 · January 24th, 2008, 04:30 PM

Hey guys I need some advice...

I am being told by mutliple sources that running my KB 6.8cc pistons on GT-40 heads with a standard fel-pro HeadGasket is going to create to high of compression to run JUST 93 octane for a daily driver. At the sametime I have a few others saying that it can be done.... can anyone clear this up for me?

woody1 · January 24th, 2008, 04:51 PM

Bore size? 4.00, 4.030, 4.040 etc
6.8cc dome?
CC of the head
what is a standard fel pro head gasket? .041, .047, .039??????
Deck Height? .010 in the hole, .020 in the hole etc etc ???

viper3508 · January 24th, 2008, 04:56 PM

6.8cc dome piston
Gasket= 4.145" bore, .04" compressed thickness (or-8.7cc)
pistons and block are top decked (piston is .0" deep)
they are IRON gt-40s as well.

woody1 · January 24th, 2008, 04:58 PM

Originally Posted by viper3508

6.8cc dome piston
Gasket= 4.145" bore, .04" compressed thickness (or-8.7cc)
pistons and block are top decked (piston is .0" deep)
they are IRON gt-40s as well.

need to know combustion chamber size, they vary greatly regardless of ford published numbers, also need the bore size

viper3508 · January 24th, 2008, 05:06 PM

61cc head, 4.030 bore, stroke 3"

woody1 · January 24th, 2008, 05:09 PM

10.9 and you will have trouble on 93 with that iron head. Is the dome hollow or solid? If solid, depending valve relief depth, you can mill the dome. And no moving to a .060 gasket wont help, it will help in terms of static cr, but .060 quench is a no-no

viper3508 · January 24th, 2008, 05:27 PM

well I dont really know what a quench is... however, the dome is solid as far as I know.

January 24th, 2008, 04:30 PM	#1
viper3508 Newbie Join Date: Oct 2007 Posts: 43 iTrader: 0 reviews	C/R ratio Hey guys I need some advice... I am being told by mutliple sources that running my KB 6.8cc pistons on GT-40 heads with a standard fel-pro HeadGasket is going to create to high of compression to run JUST 93 octane for a daily driver. At the sametime I have a few others saying that it can be done.... can anyone clear this up for me?

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January 24th, 2008, 04:51 PM	#2
woody1 Enthusiast Join Date: Nov 2006 Posts: 559 iTrader: 0 reviews	Bore size? 4.00, 4.030, 4.040 etc 6.8cc dome? CC of the head what is a standard fel pro head gasket? .041, .047, .039?????? Deck Height? .010 in the hole, .020 in the hole etc etc ???

January 24th, 2008, 04:56 PM	#3
viper3508 Newbie Join Date: Oct 2007 Posts: 43 iTrader: 0 reviews	6.8cc dome piston Gasket= 4.145" bore, .04" compressed thickness (or-8.7cc) pistons and block are top decked (piston is .0" deep) they are IRON gt-40s as well.

January 24th, 2008, 05:06 PM	#5
viper3508 Newbie Join Date: Oct 2007 Posts: 43 iTrader: 0 reviews	61cc head, 4.030 bore, stroke 3"

January 24th, 2008, 05:09 PM	#6
woody1 Enthusiast Join Date: Nov 2006 Posts: 559 iTrader: 0 reviews	10.9 and you will have trouble on 93 with that iron head. Is the dome hollow or solid? If solid, depending valve relief depth, you can mill the dome. And no moving to a .060 gasket wont help, it will help in terms of static cr, but .060 quench is a no-no

January 24th, 2008, 05:27 PM	#7
viper3508 Newbie Join Date: Oct 2007 Posts: 43 iTrader: 0 reviews	well I dont really know what a quench is... however, the dome is solid as far as I know.

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