hydraulic clutch without a kit

Will do for sure. Actually there are two ways to skin the cat (= using a Chevy bearing):

1.) use an 18-spline bearing retainer and turn it down slightly: tube diameter is 1.417 and ID of bearing is 1.375-1.379. I'd turn it down to 1.360 to have some play.

2.) use a sleeve on the 23-spline bearing retainer (tube OD is 1.248) and (tack)weld it to the retainer.

You just need to measure the distance to the retainer face and use the appropriate shim amount or make a single thick shim.