I am using one of these in the Wagon's PS plumbing:
https://www.summitracing.com/parts/der-33601 Notice that it is stacked plates with fins between each pair of plates. Those are not quite as strong as the pure stacked plate design, but are reportedly better at dumping heat.
Mounted it in the 'pie plate' opening that all of these Wagons & J-Trucks have:
Some tricky plumbing got it connected to a pair of bulkhead fittings int he core support:
I don't have a lot of faith in the heat-sink style of cooler for long term heat generation. They're likely fine for a PS system in continuous use or short term drag race or Auto-X trans use, but I'd just rather not. I'm in the process of removing one that was used for trans cooling on the Wagon. I find that I am liking using the dead-soft 3/8" aluminum tubing for cooler plumbing. Bends and flares nicely, and rejects heat better than does steel tubing.