I currently have 26x10.5 ET streets that are about 3 1/2 years old and worn out..(bought those back when I was still running a 305). The best 60' times I've gotten with the 383 is 1.75 range. I think I should be able to get into the 1.6 range fairly easy and maybe drop .1-.2 sec off my 1/4 mile time with new tires and better traction. I have some moroso springs I still need to install, that should help too. I trap at about 5800-6000rpm's and normally shift at 5800 rpms.
I'm sure I could use a bigger tire with my current setup but not sure what size would be best. Look at my signature for my combo, rims are 15x8 w/4.5in backspacing. I thought about going with a 28x11.5 but thought maybe I would be under geared with that tall of a tire? Or maybe 27x10.5 might be a better match with the 3.73 gears? I think I would be best off with 4.11 gears and a 28' tall tire but I don't want to put the money into changing gears right now. Any thoughts or suggestions would be appreciated..thanks

 

Don't assume the tire size is the exact size. The 28 x 9 ET drag tires are actually 27.3" tall. Get the tire specs from the MT web site before deciding on a tire size.

DOT tire and drag tires have a different width measurement. Drag tires are measured across the tread and the section width is always wider. DOT tires are measured across the section and the tread width is always smaller. A 9" wide drag slick can have more rubber on the ground than a 10.5 DOT tire.

Your shift point/trap rpm are roughly the same so there's no reason to go to a taller tire unless you can go to a deeper gear in the diff at the same time. Go with a 28" tall tire and 4.11 gears. The taller tire will give a bigger footprint on the ground from front to rear of the tire and the 4.10 gears will give more torque multiplication to get you off the line.