Strange Ultra Case 9" Ford Center Section
HD 40 Spline Lightweight Steel Spool
35 Spline Pro Gear & Chrome Moly Yoke


Part Number: PRF225

Designed Specifically For Drag Racing
This Center Section May Not Fit Your Housing
Refer to the clearance diagrams shown on this page

Pro Mod
Top Dragster
Drag Radial
Outlaw 632
Radial vs The World
Radical high horsepower vehicles

9 1/2″ Gear Option
Check Gear Clearance Diagram

• Professional assembly
• ARP ring gear bolts
• Shipped in protective container

Ultra CaseN1912
• 3.812″ bore
• 206-T4 aluminum
• Extra large oil channel
• Critical areas heavily reinforced
• Billet aluminum main caps
• Solid steel adjuster nuts
• Designed & machined by Strange
• Cast in the USA

Tapered Bearing SupportN1950A
• Billet 6061-T6511 aluminum
• Drilled & tapped for 5/16″ & 3/8″ pick-up sensors
• For 9″ & 9 1/2″ gear sets
• Clear anodized finish

3/8″ Sensor Holes Were Added to Supports in 2021

HD 40 Spline Lightweight SpoolD2002
• 2.250″ bearing journal for additional load capacity
• Lightened to eliminate unnecessary weight
• Forged steel

Choice of 9″ 35 Spline Pro Gear

Chrome Moly Yoke & U-BoltsU1604 / U1610
• For 1350 series u-joint

Part Options
Pick-up Collar
1 magnet – U1614
2 magnet – U1614-2
4 magnet – U1614-4
8 magnet – U1614-8

9″/9 1/2″ taper/ball support w/spacer – OPRF26
Load bolt (Not for lightened gears) – N1910H
9 1/2″ Pro Gear – OPRF23
Gasket – H1111 / H1111S

Labor Options
Lighten ring gear – D3596
MicroBlue gear set – D3598G
MicroBlue gear set & bearings – OPRF42


Strange has developed the 206-T4 heat treated Aluminum Ultra Third Member for racers who value maximum gear life. The design moves both pinion bearings into the case, offering far greater support to other designs where the bearings are outside the case.

To further reduce flex the pinion support has a very precise fit to the case bore. This, coupled with an oversized tail bearing, the pinion gear is held firmly in place. This hold the pinion gear in proper alignment with the ring gear even under the most extreme conditions.

This case can utilize 9” and 9 1/2” ring gears, and can use 10” development gears with the proper pinion support. Strange Ultra Centers have a provision to use an optional load bolt if required.

The 3.812” bore Ultra case is designed for a heavy duty lightweight 40 spline steel spool that features a thicker wall on the bearing journal to eliminate the possibility of collapse under the most abusive conditions. It also allows the use of a aluminum 40 spline spool were applications permit.

The 3.812” is available in a special lightened version with a ball bearing pinion support commonly used in Pro Stock cars. Ball bearing supports are an option on non-lighten cases as well. For a Funny car requiring a coupler cover, a support with a built-in cover is an option. A special 4.00” bore case is available to suit the Strange L6000 Drop-out Live Axle.

Strange PRF215 Ultra Third Member with a 28 spline pinion gear is an option for those who need the use of those particular gear ratios.

Guidelines and Torque spec

You may also like…

  • Upgrade To 9 1/2″ Large Stem Pro Gear For Strange Ultra Case, Billet Case or Live Axle

    PN : OPRF23
    Read more
  • Upgrade To Tapered / Ball Bearing Pinion Support For Ultra Case Center Section

    PN : OPRF26
    Read more
  • Upgrade To Aluminum 40 Spline Spool For Center Section With 3.812″ Case

    PN : OPRF29
    Read more
  • Upgrade To Heavy Duty Cap Kit

    PN : OPRF37
    Read more


Return Codes to use: