I have a Champion in my '70 Sport Satellite with warm 383 and it's seems to work just fine. Both of the tranny cooler fittings (flare) where smashed flat under the nut that was on the fitting during shipping. This means it was done during construction/storage but I was able to get them round enough not to leak.

I just looked and Summit has a crossflow (18"X22.5" core) for $144. I have one of these in my Demon and it works very well. Construction seems to be a little higher quality (welds anyway). I called Summit and confirmed that they are welded tanks and not epoxy. They don't have petcock or mounting tabs but that's not hard or expensive to take care of.