Will 28" tires to 26" hurt my ET ?

I ran my car last weekend for the first time at the track. Currently running a 28x12.5 drag radial, car was spinning but ran 11.40's.
My buddy gave me a set of 26x10 slicks with lots of life left in them. If I drop 2" shorter tire, will this improve my ET or hurt it ?

Some info on the car....
peek TQ is 4250rpm
peek HP is 5800rpm
gear is 3.55
was crossing finish line at about 6200rpm with 28" tire