Complex sentence: Johnston was the equal-leading wicket-taker in the Tests (27 along with Lindwall) and Australia's leading wicket-taker in the first-class matches with 102, making him the last Australian to take a century of wickets on an Ashes tour.
Split into simpler sentences: Johnston was the equal-leading wicket-taker in the Tests (27 along with Lindwall) and Australia's most prolific wicket-taker in the first-class matches with 102. The latter feat made him the last Australian to take a century of wickets on an Ashes tour.