Will Skyjacker 2.5" springs support big block?

[Chevy3+3]

I plan on bumong my 88 1 ton up about 2-3" in the front. I here many speak highly of Skyjacker springs and they make a 2.5" front lift spring set and rear block kit for a 1 ton. Since it is made for the 1 ton will it support the 454 alright? I don't want to spend the money if the springs will sag under the extra weight because I really want that 2.5" in height. The kits isn't cheap at $450.

Anyone have any suggestions for another front spring set? Does anyone know if the springs would be the same width as the stockers? I've heard sometimes they narrow the width of the spring and use bushings to take up the difference.

Thanks