904/727 torque converter spline counts

As a side note/ update

The trans is indeed a 18 spline count and finding a aftermarket converter was basically impossible though I may have missed a rock to turn over. I simply went down the block to have the OE unit modified.

These guys handled it for me and I’m happy with the results.
ProTorque High Performance Drag Racing Torque Converters

I have the “Pro Drive” with some of the “Bullet Race Drive” parts.
700+ HP not a problem.