I know vettes have used these for decades. I wasn't aware of astro vans using them, nor any associated failures of their use, but I can't say I'm real hip to keeping up on astro vans either.
One issue with composite springs is that they are suspectible to damage and must be protected. Just like a torsion bar, damage to them creates stress riser that can lead to failure. In a vette, the leaf is transverse and sitting on top of the diff way up in the chassis. This affords them a pretty high measure of protection compared to the astro van, or mopar application, where they are sitting out wide, low, and close to the road. Most reputable manufactures will suggest you protect composite leafs with a wrap to avoid any trouble. This could be as simple as wrapping them with duct tape, or as trick as using a shrink wrap.
Speaking of manufactuers, composite leafs are offerd by Hypercoil, Afco, Landrum, and Speedway. I don't know but they may all be made at the same place and marketed through those distributors. In any case, there are alternate suppliers out there. Also with the marketing, most, if not all of these, as are most mopar oval track springs, are based on the Direct Connection oval track design from the early-mid 70s.
Mopars oval track springs are actually designed with a 20.5" front segment. By comparison, stock B and E bodies use a 22" segment and Super Stock uses a 20" segment. So they are not a direct replacement for either, but the half inch variation from the SS design is typically not a big deal in either tire clearence in the wheel well or driveshaft slip joint fit. I've got SS hangers in my car with the oval track springs and they fit just fine.I have spoken to one guy with them who didn't like the look of the half inch varaition, so your mileage may vary. When looking at the short segment from the perspective of drag race vs handling, it provides a similar function; the shorter segment firms up the spring and provides traction assistance when launching from the starting line or accellerating out of a corner. The shorter segment also has demonstrated less dynamic wheelbase changes during cornering so roll steer characteritics become more stablized and predicatable. So like drag car, a properly set up leaf spring based mopar stock car would lift slightly under accelleration.
Brad, to your offline question about relocation impacts on handling, it is fairly minor. When figuring out the rate balance on my car, I did models of stock spring location, 1" inboard per side, and 3" inboard per side. The change in location and the resulting change in leverage means a 1" relocation causes the spring to loose an effective rate amount that is around 15-17# per side. A 3" change would be double that or 30-34# per side. IMO, these are pretty negligible changes, especially the 1" version which allows more than enough tire to prefectly fill the wheel well. Heck, even GM based oval track springs are only available in 100# increments so the odds are very high most of use will never notice a 15 to 30 pound change in rate.
TC
