TRW shows 2 different 455 BBB springs, both single coil with damper. I suspect the VS1020 is for the Grand Sport.
VS1016 is 295 lbs. per inch of deflection (a little less than stock), VS1020 is 373 lbs. per inch and will give high open pressure if you're not careful.
The reason there are not more interchanges is that the stovebolt springs are an odd OD, about 1.35". The more common 1.25" springs will work but you can't use the original collars.
