camshaft torque convertor questions

Just put an 07 motor and tranny (1.6L and auto) in my wife's 08 sedan. All sensors plugged in great, but.....as usual fuel mileage sucks. Put a new timing belt in, motor had 73K on it. We both drive about 60-65, keeping up with traffic. Mileage looks to be around 23/24. Tires are 185/60-15s. Noticed that 60 MPH is about 2300/2400 RPM.
While working on the car, we had rented a new corolla.....which got 37-39 driven the same. Ouch1 technology marches on!
Here is my question, could I get a new custom torque convertor made that was "tighter"? I'm thinking to drop my engine revs about 400-600 at 60mph should help increase the milage. Since the motor wasn't designed to run that
slowly, I would put in new cams or reground cams designed to move the torgue peak of the motor 600-800 rpm lower.
I'm from the v8 world, with an occasional air cooled bug, so I have no experience here. Im trying to do this as low budget as possible. Not going to spend thousands to get four mpg more. Hoping if there are cams they wouldn't be more the $300....no idea on a custom convertor. Cant get a new car now, the corolla would be ideal. LOL! Get a back up camera and steering wheel controls for the radio and phone.
Any input, ideas, suggestions, or experience is greatly appreciated.

that won't help your gas mileage any, nor would it be cost effective either. and the cam idea wouldn't be worth it either even if a company even remotely offered aftermarket support for this engine.

Changing a to a lower RPM lockup torque converter won't change RPM's on the road. Think of it like a manual transmission and a clutch, what RPM do you want it to be at full 100% grab and at what rpm it'll bog the motor down at and hopefully commence burnout. After you ease off the throttle like normal driving it'll lockup and turn 1:1 like a normal clutch. The only thing that will really change would be the first few seconds from a stop light will be at at a lower RPM and it might bring the RPM's down quicker during up shifts. As for Camshaft RPM, you would want the engine running exactly at the camshafts designated prime RPM. If my notes are right, Aveo's run 3,000 RPM AT 67.7MPH. So the cam is designed by really smart people to be most efficient at that ballpark highway speed to make their car look better. Changing it to a lower RPM cam that delivers the most power with the least fuel at a lower RPM won't do as well as the stock one did at similar highway speeds. Unless you want to run something like 56 mph at 2,500RPM and lower the power curve of the engine to fit a slower driving speed... I read a few different places that Aveo's get the best MPG in high gear at 47 mph. That's stupid. I run 47 up and down my driveway. Only way to bring RPM's down is to change high gear in the tranny which isn't gonna happen or change to a high ratio differential gear in the tranny which isn't gonna happen.... Or get taller tires..... I did. My Aveo runs 2,500rpm at 67 mph.... But I usually run at 80 which brings it back to 3,000. I'm also from the mega power v8 world. It used to hurt my feelings runnin at 3k on the highway... It's a happy little 4banger that's made for it. Run expensive synthetic oil, keep on the cheep maintenance, free up resistance/power waist where you can. Intake, exhaust, header, Underdrive pulley, LED's in everything, fold mirrors back, take off hubcaps hahaha..... Read up on mpg stuff. If you can modify and change the car do the same mph with less throttle percentage/fuel delivery.... Same speed less fuel. You gained mpg.

Edit: did some reading and the similar 2010 Suzuki Forenza has a 3.55:1 gear ratio vs our 3.94:1. That higher ring and pinion might fit..... Don't know, but that's a possibility to correctly lower RPM's. If it was the same tranny case and stuff, that would bring it down from 3,000 to 2,700 RPM at 67.7 mph. If there was a similar car with a lower gear, I'll tear mine apart and find out. Oh, I use 67.7mph because the rpm math comes out to easy numbers.

Thanks for the replies, I appreciate it. LOLA, I'm from the v-8 world too, and was thinking of a "tighter" convertor. I know one place that would do it, but then the motor couldn't run it, LOL. A tighter convertor, could drop cruising revs by four hundred revs, thats why I want to use different cams. I have slightly bigger tires, but my wife drives half hiway, half city. The taller tires kill acceleration also. whatever we would gain on the hiway, we would lose in the city.
I'm going to try all the tricks I can think off, and find.........thanks again.