i have a 2002 camaro z28 ls and manual t56 transmission. the car in sixth gear has to be going 65 mph or it lugs. what gear ratio would be betterso i can stop driving in 5th gear. i was told 411

 

Well stock I believe they are 3:42s like my car (2001 SS 6 speed) so going to a 4:11 is a pretty big jump.
I'm thinking about doing 3:90s or maybe 3:73s in mine.
At what speed do you want to be in 6th gear?

 

Do you have a cam and a tune in the car? I have had both Lt1 and LS1s with 6 speeds and I can drive in 6th gear at 60 MPH with no issue. I don't down shift until 55 or so and that because of the drowning sound. Sure it is slow to accelerate but that is why you down shift when you need to speed up quickly. 4:11 would render 1st gear almost useless except for racing. My LS1 has a stage 1 Cam and a tune and only gets about 24 MPG on the highway. It would have to be at lease a stage 2 or mid size CAM to cause an issue.

I wonder if your LS is running 100% at low RPMs. There are a lot of things that can go wrong that you would only feel under light loads at low RPMs. Problem with the fuel pressure regulator, small vacuum leaks a slight stretch in the timing chain all come to mind. Honestly, light load surges can be one of the hardest things to track down. I used to hate those work orders. There is just so many things it can be.

 

That's where I'm at,cam is pretty lumpy and with stock gearing I'm lobing out below 65 mph.

 

check plugs and plug wires, are you getting any service engine lights? maybe change fuel filter as well. if car has set for long time like many months you might consider having injectors cleaned and flow tested.