This is the direct ratio, from FASA'S STCS to The normal amount of Tran and Imp Boxes ADB put on SFB ships.
For Personnel Transporters, add 1 Tran Box per 2 Personnel Transporters
For Combat Transporters, add 1 Tran Box per 2.5 Combat Transporters
For Cargo Transporters, add 1 Tran Box per 3 Cargo Transporters
For Emergency Transporters, add 1 Tran Box per 4 Emergency Transporters
For Impulse Engines, it starts off at a simple 1:1 Conversion Ratio, then becomes more simple and abstract as the STCS Impulse Power increases:
STCS Power: SFB Imp Boxes
1: 1
2: 2
3, 6: 3
4, 8: 4
5, 10: 5
11-27: 6
28-31: 7
32: 8
Each +2 STCS Power: +1 Imp
STCS to SFB Conversion: Transporter and Impulse Counts
Re: STCS to SFB Conversion: Transporter and Impulse Counts
Also, for further conversion reference, here's MPR to Move Cost/Turn Mode
1/5: .05/AAAA
1/4: .1/AAA
1/3: .15/AA
1/2: .2/AA
1/1: .25 or .33/A-B
3/2: .25 or .33/A-B
2/1: .5/B-C
3/1: .67 or .75/B-D
4/1: 1/C-D
5/1: 1.25 or 1.33/D-E
6/1: 1.4 or 1.5/D-E
7/1: 1.67 or 1.75/E-F
8/1: 2/E-F
9/1: 2.25/E-F
10/1: 2.5/E-F
1/5: .05/AAAA
1/4: .1/AAA
1/3: .15/AA
1/2: .2/AA
1/1: .25 or .33/A-B
3/2: .25 or .33/A-B
2/1: .5/B-C
3/1: .67 or .75/B-D
4/1: 1/C-D
5/1: 1.25 or 1.33/D-E
6/1: 1.4 or 1.5/D-E
7/1: 1.67 or 1.75/E-F
8/1: 2/E-F
9/1: 2.25/E-F
10/1: 2.5/E-F