I have 4 non turbo 6.2 vehicles on the road currently. 2 M1009 trucks with stock gears, a M715 with 5.87 gears and a 2wd Suburban with 3.42 gears. Each one is different in how it drives and the power it feels like it makes and when it makes it.
The two M1009 trucks feel totally different. Both have 33 x 12.5 tires. One with a rebuilt IP and newer injectors has a K&N air filter and the pump turned up to put a little black smoke out if I get on it any from a stop. The other all stock with an older IP will out run it in town all day long and just feels faster all the time. It should be the other way around.
RED is the fast one. My son redid it 5 years ago, drove it daily once he got his license to high school and took it to College this past summer. He just walked in the door after driving it 160 miles round trip to see his girl friend. He cruises at 68-70 mph. He has put almost 20,000 miles on it all over Texas doing mountain biking.
However, almost all of that driving is at 1,000 feet elevation or lower. He took it to Palo Duro Canyon almost two years ago which is at 4,000 elevation. He said it was a dog. He was taught by me not to make black smoke. So driving by the exhaust in the mirror. He was down to 62-65 cruising on flat land and much slower on hills. Acceleration was almost non existent. Being in Colorado. What elevation are you at?
if you are wanting grunt at any speed at elevation. A non turbo diesel just isn’t going to do it. Yes, a gear ratio change will make it better. So will a manual transmission. A NV4500 will make it feel like more power. I have one behind a 6.2 in my M715. Dropping a gear on a hill and punching the throttle is nice. It sounds cool but I probably don’t gain much speed compared to just lugging it out.
I also have a 6.5 powered 4x4 3/4 ton square body Suburban. 3.73 gears and 35 inch tires so it is basically the same as a 3.42 gear ratio. Add in a 4L80E and I am at 1,800 at 70 mph in OD with the converter locked. A bit lower rpm than a M1009. I have a Banks turbo on it. Normal driving I don’t get any boost until I am above 50 mph. Hook up a trailer that is loaded or try dragging a M35 around a field and I have boost at 0 mph. It is a tremendous difference.
I want to turbo everything I own. Gas or diesel.