Jerry, are you saying that Pontiac used a transmission fluid heat exchanger mounted in the lower radiator hose on the WS6 Firebirds? I hope that you can find it, because that's one I've never heard of before and I'm wondering why the OEM designers wouldn't have simply used the tried & true radiator HX. Just seems strange. If you find the beast and send info to Jack perhaps he can post pictures of it, unless he decides to make it a two man protest on posting pictures ;) :HMMM:
Can you provide a specific reference to the marine application you're referencing, like a direct link to the web site showing the product? I'm not familiar with any boat engine using a radiator - thought they all did the once through pulling from and exhausting to the body of water they're floating in but I may well be wrong.