3890 is LONG, like 24 inches extended I think with 9 inches of travel. I've been doing alot of shock research recently and my car (@15.5 inch ride height between shock mounts) needs a 3860 from Afco (6 inches travel, closer to 20" fully extended. They also make a 3870 which is in between the two.
You need to take measurements of your suspension at ride height, with weight in the driver seat, as well as full droop/extension, and go from there.
11.48 @ 120 with a 1.80 60' 318, stock 1.88 heads, stock 904, Pump Gas, 13 lbs of boost.
9.94 @ 134, 318 on pump gas, 14 lbs w/ Eddies, transbrake 727, 3600 lbs, 3.54 gear and 28's.
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