Higher compression = better milage?
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Freshman User
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Higher compression = better milage?
I was doing some research on 460 engine building and discovered that the 80's 460's have a weak 8.5 comp. ratio. Could this explain why my 460 does not seem to have the power it should but still get about 7mpg? I know i have no OD in my t18 and i have 4.10s in the rear, but around town i should get at least 11 or 12. The motor has been freshened and does not use oil. I just recently did a complete tuneup. The only mod on the engine is a edelbrok 600 carb( i did not put this on...previous owner). My question is if i put pre-1973 heads on the motor with a little port work and a good intake and headers, i know it will increase power, but will the higher compression yield better milage? I was told that higher comp. is better on gas up to about 10:1 then it starts going down after that. i did the math with my current block and pistons and the older casting heads i will end up somwhere around 9.8:1. Any experience with this anyone? thanks
Postmaster
Joined: Jul 2003
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From: Pittsburgh
The higher the compression ratio the higher your fuel mileage and power will be SO LONG AS the fuel you intend to run can support the compression ratio. If you run into detonation your fuel mileage will go down the drain.
On regular fuel with iron heads 8.5 or 9:1 is about all the more you want to run (YMMV). If I were you something I'd look into is the jetting on that edelbrock 600. Just because someone put it on there doesn't mean they set it up and a properly setup carb will return better mileage and power. (Edelbrock pre-sets their carburetors for a 350 SBC)
Justin
On regular fuel with iron heads 8.5 or 9:1 is about all the more you want to run (YMMV). If I were you something I'd look into is the jetting on that edelbrock 600. Just because someone put it on there doesn't mean they set it up and a properly setup carb will return better mileage and power. (Edelbrock pre-sets their carburetors for a 350 SBC)
Justin
Last edited by hoxiii; Feb 22, 2007 at 10:12 AM.
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Thats what i figured...i am fine with running 89 or so in the truck. I have a mustang thats 9.0:1 with a cam, roller rockers and so on and that runs on 87 with iron heads. I usually run 89 for peace of mind, but no pings with 87. I just had the edelbrock apart and i could not read the jet numbers on the jets...i did not have a magnifiying glass so i just put it back together. what should i start with for jets in that thing? All my friends do holly carbs and dont know much about edelbrocks...i'm new to carbs myself aswell. thanks for the reply
