84v54 is a 2.4T piston.

Here's a copy of my piston cross reference listing (still incomplete):

Porsche 911 Piston Reference numbers

yr/model size Mfg CR P/N
2.0 65-67 80mm Mahle 80v37
2.0 E 69 80mm Mahle 80v79
2.0 S 67-68 80mm Mahle 80P26
2.0 S 69 80mm Mahle
2.0 906 80mm Mahle 10.3 80P26
2.0 T 68-69 80mm Mahle
2.2 E 84mm Mahle 84v51
2.2 S 84mm Mahle 84p8
2.2 T 84mm Mahle 84V48
2.2 T 84mm KS 84072
2.4 T CIS 84mm Mahle 84v58
2.4 E 84mm Mahle 84072
2.4 S 84mm Mahle 84P11
2.4 T 84mm Mahle 84V54
2.4 T 84mm KS
2.7 CIS 90mm Mahle 8.1
2.7 CIS 90mm KS 8.1 90202
2.7 CIS 90mm Mahle 8.5 90L58
2.7 CIS 90mm KS 8.5 90208
2.7 RS 90mm Mahle 8.5 90P27
3.0SC 95mm Mahle 8.5 93L7
3.0 SC 95mm Mahle 8.5 95L70
3.0 SC 95mm KS 8.5 95136
3.0 SC 95mm Mahle 9.3 95L67
3.0 SC 95mm KS 9.3 95152
3.0 RSR 95mm Mahle 10.5 95P30
3.0 SC 95mm Mahle 9.8 95L70
3.0 Turbo 95mm Mahle 6.5
3.2 Carrera95mm Mahle 9.5 95p36++
3.2 Carrera95mm KS 9.5 95175
3.2 Carrera95mm Mahle 10.3 95p36++
3.2 Carrera95mm KS 10.3
3.3 turbo 97mm Mahle 7.5
3.6 100mm Mahle