Fuel Mileage
Burning Brakes
Joined: Oct 2006
Posts: 1,044
Likes: 0
From: Henrico VA
I looked at reducing internal friction, improving ignition, improving atomization, reducing load, and using gearing. My ratios are 0.64 (T-5 with AMC gear in it) * 3.36 (rear end) = 2.15. I run royal purple, NGK Iridium Spark plugs, and the complete Pertronix Ignition kit, as well as stators on my air cleaner base, so the hi-rise intake actually helps my fuel atomize even more. (And I put the air dam as well as clutch fan back on after Bubba took them off.) The guy that built my transmission said that the Rochester Carbs were like simplified fuel injection. They are highly sophisticated. A Chevy 350 is optimized for 2000 rpm. With my intake it is optimized for 2200~2300 rpm. When I told him that I still have the Rochester, he said 1500 to 2500 rpm. I can be in fifth gear comfortably as low as 38 mph and try to shift as soon as it'll be near 1300~1500 rpm. I am at 2000 rpms at 75 mph. I do coast A LOT. I get behind these people that think they have all day and just stick it in neutral and I still have to brake! I haven't had a successful highway trial yet (always get stuck in traffic even on the way to Boston), but it has to be in the upper twenties.
Racer
Joined: Dec 2003
Posts: 263
Likes: 0
From: Kernersville Nc
I seriously get 20 mpg on my 454/400 trans vette. Most people are skocked at this number but it is correct. Keep in mind it is an original stock motor. My pro street camaro with a built 355 igets 14mpg. These numbers are driving normal doing the speed limit not full throttle.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Properly tuned there is no reason a stock or near stock or warmed over 350ci should get 14 mpg. Get an LM-1 and tune the carb correctly. I got 24mpg with my 550HP 406ci on the highway @ 80mph with an 825cfm Race Demon carb. The 3.08 and .64 over drive making the motor turn 2000RPM @ 80MPH helps but proper tuning of the motor is the key 
Racer
Joined: Dec 2003
Posts: 263
Likes: 0
From: Kernersville Nc
Properly tuned there is no reason a stock or near stock or warmed over 350ci should get 14 mpg. Get an LM-1 and tune the carb correctly. I got 24mpg with my 550HP 406ci on the highway @ 80mph with an 825cfm Race Demon carb. The 3.08 and .64 over drive making the motor turn 2000RPM @ 80MPH helps but proper tuning of the motor is the key
350 specs: 1970 chevelle camel hump heads 4 bolt main block, 11 to 1 pistons, 486 lift comp cam. wiend team g highrise manifold 750 holly vac secondaries, accell blueprint dist with super coil ad msd6al ign.
Race Director
Joined: Oct 2000
Posts: 15,044
Likes: 79
From: central FL, near the beach.
I looked at reducing internal friction, improving ignition, improving atomization, reducing load, and using gearing. My ratios are 0.64 (T-5 with AMC gear in it) * 3.36 (rear end) = 2.15. I run royal purple, NGK Iridium Spark plugs, and the complete Pertronix Ignition kit, as well as stators on my air cleaner base, so the hi-rise intake actually helps my fuel atomize even more. (And I put the air dam as well as clutch fan back on after Bubba took them off.) The guy that built my transmission said that the Rochester Carbs were like simplified fuel injection. They are highly sophisticated. A Chevy 350 is optimized for 2000 rpm. With my intake it is optimized for 2200~2300 rpm. When I told him that I still have the Rochester, he said 1500 to 2500 rpm. I can be in fifth gear comfortably as low as 38 mph and try to shift as soon as it'll be near 1300~1500 rpm. I am at 2000 rpms at 75 mph. I do coast A LOT. I get behind these people that think they have all day and just stick it in neutral and I still have to brake! I haven't had a successful highway trial yet (always get stuck in traffic even on the way to Boston), but it has to be in the upper twenties.
.
young
which hi-rise intake do you have? i want to replace my performer 2101 which has poor fuel distribution
Burning Brakes
Joined: Oct 2006
Posts: 1,044
Likes: 0
From: Henrico VA
I have an Edelbrock Performer Hi-Rise Intake. It is a clone of an LT-1 intake from the early 70's that routinely go for $400. It is dual-plane so I'm supposed to have a pretty wide powerband, but I probably lost some low end torque when I got all the hi-end. I know that I can cruise around ~1000 rpm in 5th gear because of my mild cam, so I must have some torque.
I bought it from a guy at a car show for $100 along with the chrome valve covers. I think it'll go for twice that for a new one.
I bought it from a guy at a car show for $100 along with the chrome valve covers. I think it'll go for twice that for a new one.
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