Compression vr Gas
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Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Compression vr Gas
What compression ratio is the break point between regular and premium gas. I am building a 390 and have some different heads, gasket thickness options to choose between. I do not want the ratio to be high enough to require premium gas. I can go as high as 9 1/2 with what I have.
Thanks for your imput.
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John
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In the cool still quiet of night, you can hear chevies rusting away.
Thanks for your imput.
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John
jowilker email me
[link:www.ford-trucks.com/users/jowilker|My Club FTE Page] Member since 01 01
[link:www.ford-trucks.net/users/jowilker/NCFTE.html|NCFTO] North Carolina Ford Truck Owners Group
In the cool still quiet of night, you can hear chevies rusting away.
More Turbo
Joined: Jun 2001
Posts: 571
Likes: 1
Compression vr Gas
are you saying that you can take your compression all the way up to 9.5? I am not sure but I have heard that you can use regular gas as long as the compression is less than 10:1. I have no experience in this department this is just what I have heard, so....
Cargo Master
Joined: Jul 2000
Posts: 2,281
Likes: 18
From: Northern California
Compression vr Gas
It really depends on a number of factors.
I ran reg gas on my w/ about 10.5:1 but I knew in advance that the CR was going to be high for reg gas.
I blocked the exhaust crossover off so the intake would be cooler
polished the chambers
large rad & edelbrock alum water pump
zero deck the block so the pistons have more squish effect
custom curved dist
You can also help with colder plugs.
You can get to 10:1 but you should do some planning first. keeping the intake cool, custom curved dist and max squish effect are probably the most important. Keeping the engine cool is a big factor too.
I'd get the book "how to build horsepower vol II, carbs & intakes" He has all kinds of info about this and it's < $20.
I ran reg gas on my w/ about 10.5:1 but I knew in advance that the CR was going to be high for reg gas.
I blocked the exhaust crossover off so the intake would be cooler
polished the chambers
large rad & edelbrock alum water pump
zero deck the block so the pistons have more squish effect
custom curved dist
You can also help with colder plugs.
You can get to 10:1 but you should do some planning first. keeping the intake cool, custom curved dist and max squish effect are probably the most important. Keeping the engine cool is a big factor too.
I'd get the book "how to build horsepower vol II, carbs & intakes" He has all kinds of info about this and it's < $20.
Thread Starter
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Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Compression vr Gas
Thanks guys, I just have two blocks and 4 sets of heads to choose from. Nothing radical about this motor, but I didn't want to be stuck in the premium gas pump line.
Why buy the books when you can ask the experts here?
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John
jowilker email me
[link:www.ford-trucks.com/users/jowilker|My Club FTE Page] Member since 01 01
[link:www.ford-trucks.net/users/jowilker/NCFTE.html|NCFTO] North Carolina Ford Truck Owners Group
In the cool still quiet of night, you can hear chevies rusting away.
Why buy the books when you can ask the experts here?
http://www.clubfte.com/users/jowilker/USFlag.gif
John
jowilker email me
[link:www.ford-trucks.com/users/jowilker|My Club FTE Page] Member since 01 01
[link:www.ford-trucks.net/users/jowilker/NCFTE.html|NCFTO] North Carolina Ford Truck Owners Group
In the cool still quiet of night, you can hear chevies rusting away.
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