This is basically an interchange between the Paxton part numbers and the Ford part numbers. This is by no means conclusive and is only provided as an indication, as design differences may be more subtle than those indicated in the diagrams. It’s more of a guide rather than a definitive reference.
NOTE:- The Ford numbering system is typically B7A-99597-A where the B7A prefix represents B for the 1950’s decade, 7 for the year within the decade and A for product identification (A = passenger cars, S = Thunderbird). The 99597 is the basic number where the 99 represents the supercharger group, and 597 represents the unique ID for the part. The suffix –A indicates design differences (A is the first issue). For the sake of this interchange only the basic number is detailed for the supercharger parts.
The left hand number represents the numbering on the following McCulloch schematic. Notes explaining differences follow the interchange section.
1 58025 99597 Housing Assembly – bearing.
2 100021 99662 Seal
58068 99657 Valve Assembly, Control (1)
3 58034 Valve, Control (1)
4 58043 Diaphragm, Control (1)
5 103983 Ring, retaining (1)
6 58046 370948-S Washer, wave
7 104025 Screw, set 8-32 x ½ (2)
8 58045A 99653 Shaft, Control (2)
58075B Control cap service kit (7)
9 58042B 99651 Cap, Control
10 102462 O-Ring (2)(8)
58076 Control spring service kit (7)
11 58044 99652 Guide, Control spring (2)
12 58073 99641 Spring, Control
13 58074 Spring, Conical (2)(9)
14 58048 99647 Spring, Lever
15 58050 99645 Retainer, Control lever spring
16 58081 99650 Lever, Control
17 101497 44710-S Nut, Hex, 3/8-32 (2)
18 101991 370946-S Screw, fil hd, 10-24 x 1/2
19 58063 99658 Valve, Regulator
20 58069 99660 Spring, Regulator
21 58065 99659 Screw, Seal
22 58038 99624 Multiplying Lever Assembly
23 58033 99654 Ring, Retaining
24 58008 99623 Piston
25 101863 87069-S O-Ring
26 103938 87099-S O-Ring
27 58020 370950-S Shim, .089 to .091
58020A 370951-S Shim, .094 to .096
58020B 370952-S Shim, .099 to .101
58020C 370953-S Shim, .105 to .107
58020D 370954-S Shim, .111 to .113
58020E 370955-S Shim, .117 to .119
58020F 370956-S Shim, .084 to .086
58020G 370957-S Shim, .079 to .081
58020H Shim, .123 to .125
28 58024 99598 Carrier Assembly, Race (3)
29 58021 37058-S Ring, Race Carrier
30 58031 99633 Bumper
31 58029 99635 Driver Assembly, Ball
32 101556 359118-S Pin, Roll (press fit)
33 58012 99655 Output Shaft Assembly (4)
33A 58028 99636 Ring, Outer seal (4)
34 58058 99656 Ball Drive Kit (matched set of 5) (4)
35 58084 99594 Scroll Assembly (3/8 oil drain) (5)
36 58060 Race, Outer (matched pair) (4)(7)
37 58019 99622 Gasket, Bearing Housing
38 102195 99639 Pin, dowel
39 37018 99661 Shim, Impellor, .026 to .028
40 58040 99596 Impellor
41 100350 356184-S Washer, flat, 5/16
42 100271 34806-S Washer, lock, 5/16
43 102199 304721-S Screw, hex hd, 5/16-24 x 1 1/4
44 58002 99595 Cover, Scroll (6)
45 102108 304720-S Bolt, hex hd, 5/16-18 x 1 1/4
46 100271 34806-S Washer, lock, 5/16
47 100350 356184-S Washer, flat, 5/16
48 103059 370949-S Screw, fil hd, 10-24 x 5/8
49 103850 Plug, pipe, 3/8 (7)
100432 Plug, pipe ¼ (earlier models) (7)
Note 1: Control valve assembly, comprising Control Valve (Item 3), Diaphragm (Item 4) and Retaining Ring (Item 5). Ford supplied this as the complete assembly without part numbers for the constituent parts.
Note 2: Different control shaft components used on Ford. See diagrams below.
Ford Control Shaft
Paxton Control Shaft
Note 3: Race carrier assembly different. Ford part number is 99598. See diagrams below.
Ford Race Carrier
Paxton Race Carrier
Note 4: Output shaft assemblies different. Ford part number is 99655. See diagrams below.
Ford Output Shaft
Paxton Output Shaft
Note 5: Extra posted screw on Ford unit. See diagrams below.
Ford Scroll Covers
Paxton Scroll Covers
Note 6: Extra screw on Ford unit. See diagrams above.
Note 7: Not supplied by Ford.
Note 8: Not used on VR57 superchargers. Only fitted or VR57A/B rebuilt by Paxton.
Note 9: Not used on VR57 superchargers. VR58 only.