1) We start with a 4130 Chrome-molly hardened steel hub, with large oil journals machined in to the bearing surface to increase oil flow to the bearing and throughout the entire converter.

2) All impeller fins are furnace brazed and hand TIG welded, to increase the durability of fins.

3) Two Heavy Duty Torrington bearings are placed on either side of the stator assembly.

4) The stator is then modified by adding additional lube orifice for additional cooling.

5) Inside we use a new Heavy Duty race and Heavy Duty springs and rollers are installed as well.

6) All turbine fins are precision wielded to the turbine to increase durability and strength.

7) Then 4130 chrome-molly hardened steel splines are wielded in place. These splines also have journals machined into the bearing surface to provide better lubrication to the bearing.

8) A new Hi Temp o-ring and washer are installed to ensure proper seal for lockup apply and holding.

9) The piston and damper assembly used are Heavy Duty and only the best (high temp carbon composite) lining is used. LOCKUP UNITS ONLY!

10) Finally for the cover, a laser cut re-enforcing plate is bolted and welded into place to reinforce the converter housing and provide the proper bolt pattern.

They feature hand-brazed impellers, heavy-duty stators, Torrington bearings instead of washers, a specially machined surface for additional cooling, performance extreme duty sprag assemblies, special high heat high, high friction carbon composite converter lockup clutch lining (lockup units only) and a 4140 chrome molly steel hub. These units are built tough and to your custom needs. These are not off the shelf units!

Our 9.5 inch Pro Race Series converters are available in 1.69, 2.1 and 2.5 STR in stalls from 2800 to 4000 RPM stall.

To help you choose, here is some additional information about Stall Torque Ratio. Stall torque ratio is the multiplier for torque for a short time when the car is launching. Higher STR will give a much higher torque multiplication for a very short time right at launch, but with an overall cost in efficiency at the top end. In other words, higher STR will increase your 60 ft times, but it may be at the expense of MPH at the top end. Lower STR, while it will not deliver the punch at the bottom like a higher STR, will give torque multiplication for a longer period of time and may allow you to place more power to the ground with less spinning. Additionally, the over all efficiency is much better. Where a 2.5 STR might be only 90 percent efficient above rated stall, a 1.69 would be 96 percent efficient above rated stall (both these numbers based on converter not locked). This means you put more power to the ground throughout the run down the track. Each person has different needs and goals, which is why we offer multiple STR.