OzyDuster74 chassis connector questions!!

sireland67 said
275/60/15 on 15 x 7 4.25" backspace stock 5th ave rims.
Stock A body 8.75 with big bolt axles. Hd springs with 1" lowering block, stock shackles.

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Nice! I have one inch drop calverts which probably not enough but need to pass the pits first. I may need to add a block as well. Are the hd standard height or lower?