Without the Herb Adams mod, the center of the wheel to the fender arch would be right about 16-7/8" on a Firebird which has larger/taller fender arches. Thanks
Keith at Custom Works recommends 1/2" is the most you should use for lowering blocks. I tend to agree with him. If someone wanted to do the Herb Adams mod and use 1/2" blocks, you'd be approaching 3/4" to 1" lower. Thank you