Choosing A Professionally Built Street/Strip Transmission

Weighing the value of buying a new, professionally-built automatic transmission versus taking a broken slushbox to the local transmission shop gets confusing for some enthusiasts. While most local transmission repair shops do a great job with stock transmissions with stock transmission problems, they might not be the best choice when it comes to getting dependability and power from an OE-style transmission bolted behind a hotter street/strip engine. We ran into this conundrum when it came time to choose an automatic transmission for our long-term project car, Project Sucker Punch – a 1954 Chevy Bel Air with a few surprises under the hood.


Hughes Performance specializes in making upgrade parts and components for drivetrains.

The Hughes family still owns and operates the company, much as it always has, with an emphasis on quality parts and customer satisfaction. “Customer service is the cornerstone of this family company. We pride ourselves in treating you the way we want to be treated,” proudly states the company’s literature.

We contacted Pete Nichols, Sales Manager and Tech Support at Hughes Performance to decipher what an enthusiast needs to know about selecting the correct transmission package. Nichols also explains the features and benefits of a professionally built street/strip transmission when you have a little more extra torque and horsepower under the hood.

GM Automatic Transmissions

General Motors transmissions dominated the musclecar scene and have continued to show their worth in applications that require durability. Powerglides and Turbo 400 have long held the standard as excellent foundations for top drag racing teams.

While they may look similar, there is a world of difference between a stock OE GM transmission and a professionally built GM transmission from Hughes Performance.

When it comes to street/strip transmissions, the Turbo 350 has become more of a benchmark in the last decade. With companies like Hughes Performance building street transmissions capable of living behind higher horsepower engines, the choices of transmission packages are often a balancing act between durability, efficiency, and mass. More importantly, the OE transmission hard parts need to meet reliable specs before they are used in a professional performance parts manufacturer like Hughes.

It’s just not as easy as buying a transmission core out of the junkyard and slapping in a rebuild kit and a shift kit. – Pete Nichols

“We are dealing with transmission cores to start with. That stuff that is sometimes 30 to 40-years old and you have no idea how much fly weight is on it and how much abuse it has seen in the past,”explained Nichols. “It’s just not as easy as buying a transmission core out of the junkyard and slapping a rebuild kit and a shift kit and all of the sudden you have a street/strip transmission that is going to hold 500 horsepower.”

The Benefits of a Professional Builder

Nichols explained the need for professional transmissions builders by explaining the transmission cores. “Every year that goes by these transmissions just get older and older, so there is a lot of attention to detail items that have to be thoroughly inspected, checked, verified, remeasured and possibly re-machined to restore surfaces to bring the transmission up to a truly functional level where it is not just going to function, but going to live a long, happy life for thousands of miles and years of durability.”

The Hughes crew goes though the transmissions and makes the appropriate upgrades for the customer’s horsepower level.

“We go through all of our transmission cores to check and touch, literally every part of the transmission–from front to rear and every internal component–we leave no stone unturned, so-to-speak. There are several key areas in the transmission that require attention during a proper overhaul, that your garden variety builders or local shops may not have the equipment to properly address or just may not check at all.”

Stock OE transmissions have several sub-assemblies that make up the larger unit. When it comes to inspection, each of these sub-assemblies have their own “test and checks” that must be performed.

Project Sucker Punch's Transmission Upgrades

Turbo 350 1969-79 Chevy (Part #35-1) Street/Strip Automatic

Turbo 350 1969-79 Chevy – Non Lockup (Part #GM-25HD)

“Front pumps are a good example,” said Nichols. “Pump bodies need to be lapped to ensure that they are flat. The pump stator supports need to be resurfaced to ensure that the two body halves are flat and true and not warped and creating issues with the pump assembly.”

He went on to explain that the pumps end play needed to be checked and verified, as well as checking all of the roller bearings and thrust washers. Then the gear sets need to be checked and rebuilt along with inspecting the shafts for twists, flaws, and other damage before the pump can be reassembled.

“A lot of our entry level, basic units reuse a lot of reconditioned or remanufactured original hard parts. When you get into the heavy duty and  extreme duty street/strip serious stuff is when you start getting into shaft upgrades, sprag upgrades, clutch hub upgrades and that type of thing,” he stated.

Hughes Performance Transmission Video:

One Size Does Not Fit All

Nichols is quick to point out that when it comes to horsepower and torque numbers, it’s not a one size fits all proposition. “We have advertised horsepower rating on our products, but those are kind of a nominal rating. it’s more of a guideline than a set number,” he said. “Torque plays a big factor of course, but vehicle weight also plays a big factor. Even things like rear gear ratio, rear tire size, and all that kind of information tells us what kind of load is going to be on the transmission and what the hard parts need to be capable of handling.”

Hughes makes most of their own internal components like this valve body. The other parts that are sourced are hand selected after testing to ensure they meet Hughes’ standards.

When it comes to selecting the right transmission package for your application, the crew at Hughes takes a look at the whole picture before recommending anything. “We always like to take into account the horsepower and torque production, along with the actual physical displacement of the engine,” said Nichols. “Based on the horsepower rating the tranny may look good on paper, but you actually need a little more tranny because of the torque production.”

To illustrate that point, Nichols explained, “If you have an engine that produces 400-500 horsepower, which is pretty easy to achieve these days, it’s different if you have a longer stroke, big-block piece that produces a tremendous amount of torque.”

Each Hughes transmission comes with an ID/Serial tag. Even Hughes off-the-shelf transmissions are purpose built for specific applications. It’s not a one-size-fits-all proposition.

It also depends on the style of driving the operator has. “One guy’s weekend warrior, street/strip vehicle, may only go to the track once a year and get cruised once or twice a month – and the guy is real gentle on it. Another guy’s street/strip combination might be a 9-second car that he drives two or three days to work too. He has a different idea of street/strip and we take all of that into account and tie it into a package.

Be Honest

Everything leads to honesty when it comes to selecting the right transmission for the application. Overkill and unrealistic are ideals that should be avoided when selecting the right automatic transmission. Buying too much transmission might not be the most sensible choice and buying too little transmission is a disaster waiting to happen.  “Dyno numbers are useful, but all we really need is accurate information about your vehicle. If you tell us the displacement, head type, cam profile, induction system, and those things… we have enough experience and know that these parts typically produce a certain amount of horsepower and then we can come up with a workable figure,” states Nichols.

If you’ve taken the time to find the perfect converter/transmission combination, make sure you use a quality transmission fluid in the system.

The vehicle’s combination can be sent to the crew at Hughes by filling out their tech card on the website. Then the tech professionals at Hughes performance can help customers select the best tranny for their vehicle and budget. “You don’t have to fill in all the fields, it does give the customer an idea of how much actually goes into selecting the proper transmission. The more details that are provided by the customer is directly proportional to the accuracy of the product that we can be,” states Nichols. “The data helps us select the best overall performance for the application. We are more concerned with getting people into the right product rather than into the most expensive product.”

Anticipation grows as the transmission is bolted to the back of the engine. The Hughes tranny almost looks too nice to hide it in a chassis.

Final Thoughts

Professional transmission builders like Hughes Performance have developed a strong reputation for helping customers, from the high end drag racing crowd to the street enthusiast, with solid advice to go with the high performance components. As Nichols explained earlier, selecting the right transmission is a balance between durability, efficiency, weight, and budget. For the average weekend warrior, a TH350 will probably work just fine. With three forward gears and not as much rotating mass as the TH400, the TH350 can be built to handle 500 horsepower with a few hard part upgrades and some professional machining.

New transmissions always seem to go into the tranny tunneling easier. Top it off with some quality transmission fluid and get ready to tattoo the asphalt.

Making the determination on which hard parts to upgrade becomes the challenge, and that is where the professionals at Hughes Performance really shine. Often times it is more than selecting internal parts that will determine whether a transmission survives or not. Controlling heat and selecting the right lightweight components will often make the difference in early failure or a transmission that will last for years. Guiding enthusiasts in the right direction is ultimately the largest contribution that a professional builder will make in the entire process.

Article Sources

About the author

Bobby Kimbrough

Bobby grew up in the heart of Illinois, becoming an avid dirt track race fan which has developed into a life long passion. Taking a break from the Midwest dirt tracks to fight evil doers in the world, he completed a full 21 year career in the Marine Corps.
Read My Articles

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