The clutch is 10-splined & has a diameter of 215 mm.
For B18/B20, step-out bearing with article number: 380569 (not included) is used.

Fits the following models:
Volvo B18/B20-1978Volvo 240 -1978 M40/M41/M45/M46

Fichtel & Sachs brand
w/o throw out bear

You must use withdrawal bearing 380569 for B18/B20.