Bobby Alloway of Alloway’s Hot Rod Shop Selects American Powertrain Exclusively for Manual Transmission Installs

Bobby Alloway gained his love of cars from his father who after retiring from a long term well digger career went to work as a local car salesman. Eventually and because of his love of cars, Bobby landed a job with a local Ford dealership and worked as service manager for 16 years. When the philosophy of that dealership began moving from serious customer service to placing all their resources toward moving vehicles in volume out the door, he felt the culture of the company did not fit with his beliefs and began seeking a change. Luckily, Bobby had a side job that turned into an illustrious career move for him.

For several years, he had been building from ground-up street rod project builds. While still with the dealership he won the coveted Ridler Award with his ’33 Ford Victoria Altered Street Sedan in 1985. The Ridler Award, sponsored by Meguier’s was named after Don Ridler who was hired in the 50’s to help promote the Detroit Autorama, and soon enthusiasts flocked to the event held at the Cobo Hall at the Michigan State Fairgrounds to see some of the wildest hot rods that cruised the streets of the Motor City. After passing away at an early age, the Ridler Award was established in Don’s memory. Since it has grown to be one of the most illustrious awards given in the indoor custom car show industry. The winners also receive a $10,000 cash prize, and entries must be making their first official showing at the Detroit Autorama. Best in Show Ridler Awards are judged on creativity, engineering, and quality workmanship.

After the success of his win at the Autorama, Bobby began building even more ground up project builds and as his reputation grew, the idea of going into the business of building ground-up projects full time got stronger and in 1991 he opened Alloway’s Hot Rod Shop. He has won almost every award there is to win including Battle of the Builders at SEMA, America’s Most Beautiful Roadsters, is in the Hot Rod Hall of Fame, IHRA Hall of Fame, and his builds have been featured on the covers of almost every magazine among the endemic press.

Bobby has a very strong work ethic and his business philosophy when it comes to his parts suppliers is that the products are no better than the people who sell them. When he finds a supplier who does what they say they will do, provides immediate customer support and deliver parts on time every time, that supplier has his loyalty. That’s why he has used American Powertrain exclusively for all of the manual transmissions he installs in his builds for the past five years, which is typically three to five per year for customers from across the country.

Bobby also serves on a number of builder panels, one at the SEMA Show and one at Detroit Autorama each year, and he does so in order to help preserve the influence of project builders in the industry by working with the youth who will be the future of the business.

KC Mathieu, formerly of Fast N’ Loud uses American Powertrain Exclusively for Manual Transmission Installs

KC Mathieu, owner of KC’s Paint Shop and former regular on Discovery Channel’s Fast N’ Loud, grew up at a young age helping out at his Dad’s collision shop. Mathieu says, I would him always hear Dad muttering about what hard, hot and back-breaking work it was, and telling me I needed to find another career option.”

Luckily for Mathieu, he chose not to follow Dad’s advice. Instead, he worked with his Dad and other shops until renting his own building, and starting the business that he learned to specialize in since age 12 – custom automotive paint.  A few years ago, call it chance or serendipity, Richard Rawlings, owner of Gas Monkey Garage, walked in and Mathieu’s destiny tooka new turn. When Richard landed a TV deal with the Discovery channel for Fast ‘N Loud, it was KC he turned to as a regular for custom paint segments.

“Of course this was a wonderful opportunity to showcase my passion. With the success of Fast ‘N Loud,” it reached a point that fans would line up and hang around the building when we were filming. If I headed out for lunch we would be mobbed. Three and half years of this it began to get old to have this kind of attention, so I decided to go back to what I love most and re-opened KC’s Paint Shop: Hot Rods and Restorations.”

The silver lining of leaving for Mathieu was the immediate success of his business as there was nearly nearly instant recognition of my name and expertise. Through social media, and with triple digit followers on Instagram, Facebook and You Tube, the shop exploded in growth. In fact, the company has gained so much business that KC’s staff has grown from one to nine employees adding support for accounting, marketing, vendor support, fabrication, bodywork and paint specialists.

“I am so proud of what we’ve been able to accomplish in such a short period of time,” concluded KC. Over the course of my career, some things stand out as more important like developing close relationships with my preferred automotive suppliers like the one I have with American Powertrain. About five or six years ago, I was poking around trying to find the best options for a manual transmission to install, and American Powertrain came highly recommended. Paul Unterstein and the whole team over there are so supportive and helpful from determining the best options for my builds, to quick turnaround and immediate customer support when needed. In fact, just a few days ago, I ordered two transmissions from them for a couple of projects I have in the shop. We do a good dozen vehicle service projects and two or three ground up builds every year, and if any require a manual transmission install, I call American Powertrain every time.”


Pedal Pusher: How to measure and adjust your Clutch Pedal Ratio

So you just converted your clanky old manual clutch to a hydraulic release bearing setup and you thought the pedal would be easier to operate than before. While that should be the case, it isn’t always, and that is due to geometry. Much like a brake pedal, there is a specific ratio that you need to achieve in order for the pedal to be easy to operate. For hydraulic clutch systems, that ratio is 6:1.

Manual clutches are different from hydraulics, they use a bell-crank system that increases the effectiveness of your clutch pedal. With a hydraulic system, it is all in the placement of the master cylinder push rod on the clutch pedal. The higher the pickup point is on the pedal (closer to the fulcrum of the lever), the easier it is to push the pedal. There are three key factors to this equation: pedal length, pick up point to fulcrum length, and master cylinder bore.

The bore of the clutch master cylinder is the smallest part of the equation because most clutch masters are in the 7/8” range. The bigger you go, the more effort is required to operate the master cylinder. Provided you have a 7/8” bore or smaller, the 6:1 standard is used.

To determine the ratio of the pedal, you need to do some measuring. There are two measurements you need to take: the length from the pivot (fulcrum) of the pedal to the pushrod hole (Y), and from the fulcrum to the center of the brake pedal (X). The formula is X/Y=Ratio. For example, your stock clutch pedal is 14 inches long (X), with a pickup point measuring 4 inches from the center of the fulcrum (Y). 14/4=3.5, which is 3.5:1. While this may have worked for the factory manual linkage, it is about half of what it needs to be for a hydraulic set up. In this situation, 100 pounds of foot pressure yields 350 pounds of pressure to the master cylinder. Move the pickup point up 1.75 inches, (Y measurement of 2.25”), and that same 100 pounds of foot pressure yields 600 pounds at the master cylinder.

For most applications, you can raise the pickup point by simply drilling a new hole in the pedal arm, but some cars, like GM A-bodies, use a convolute pedal design that requires welding if you want to raise the pickup point. This can be done with a ¼” tab of steel welded to the pedal in the location you want it. This process can become more complicated when you are trying to use a factory firewall hole for the master cylinder.

The sharper the angle is on the master cylinder, you run the risk of creating a bind, which no amount of pedal ratio can overcome. There are a couple of solutions for this scenario. The first is to move the master cylinder up on the firewall, decreasing the angle. This is not always possible, as the brake booster or other items that cannot be easily moved are in the way. The other option is the American Powertrain adjustable firewall mount.

The patented firewall mount allows the master cylinder to accommodate the clutch pushrod angle while being mounted above or below the pickup point on the pedal itself. Because the master cylinder is a sealed system, the angle itself does not affect the operation of the master cylinder. If you have this mount and the angle is still too great, then you have to move the master cylinder.

Here is the diagram for measuring pedal ratio. Always measure to the center of the fulcrum, pickup point, and to the center of the pedal.

This is a brake pedal, but the math is the same. On this pedal, the pickup point is 5 5/8” from the fulcrum.

The pedal measures 14 inches from the fulcrum to the center of the pedal. The math reveals this is a 2.48:1 ratio, which is ludicrously low.

To make this pedal match the 6:1 (which is also the optimum ratio for brake pedals), we drilled a new pickup point. All better.

On this 1965 Mustang, the factory clutch pedal is very close to the fulcrum, yielding a suitable ratio for the master cylinder. We were even able to use the original firewall hole.

GM A-body cars (Chevelle, Skylark/GS, 442, etc) have funky clutch pedal as shown here. If you have to change the ratio, fabrication and welding is required.


Written By: Jefferson Bryant


Red Dirt Rodz
4518 Braxton Ln
Stillwater, OK 74074
405-880- 5343

American Powertrain
2199 Summerfield Rd
Cookeville, TN 38501
1-931- 646-4836

Heil Hydra(Max)! Setting up your hydraulic release bearing

High-performance engine installed- Check. Close-ratio Tremec T56 installed- check. Clutch fully operational- nope. Well that isn’t good, it is kind of hard to put 650hp to the ground when your clutch won’t engage or disengage when you operate the clutch pedal. Unlike a mechanically-operated clutch, most modern manual transmissions require hydraulic release bearings, and if you are not close enough, you may as well be a mile off. Installing the American Powertrain Hydramax hydraulic release is not difficult, in fact it is pretty easy, but it does require some math.

The relationship between the clutch diaphragm and the release bearing is the key to a properly adjusted hydraulic set up. The release bearing should ride the diaphragm without putting pressure on the fingers, but also should not be too far away. It is pretty easy to install the bearing where it is either too close (clutch is always disengaged) or too far (clutch won’t disengage). Because these installations are not stock, you have to figure out this relationship on your own. Don’t worry, it isn’t difficult.

What you need:

  • Pen
  • Scratch paper
  • Straight edge
  • Calipers or ruler that reads to .001
  • Partially-assembled drivetrain.

To start the process, the engine must be assembled with the flywheel and pressure plate. The clutch does not have to be installed at this point, because it doesn’t matter; but if you want to do everything at once, install the clutch with an alignment tool in place. Additionally, the bellhousing must be installed on the engine as well. Begin by placing the straight edge across the center of the opening in the bell housing. Use a ruler or measuring tape to determine the resting depth of the diaphragm, this measurement is taken off of the fingers themselves where the release bearing rides. Take this measurement in three places and write the results down on the scratch paper.

Moving on to the transmission, the center alignment dowel must be installed, along with the Hydramax bearing with the notch locked onto the dowel in the fully seated position. Use a straight edge on the transmission, running across mounting surface for the bellhousing. Measure from the transmission mating surface to the face of the bearing where it rides on the diaphragm. Measure in three places and record the results.

The two sets of measurements provide the variables needed for the final calculation using the following formula. This equation will tell you how many shims are needed to achieve the proper air gap between the bearing and the diaphragm. The recommended air gap is .150-.200”, you can have as little as .100” (absolute minimum), but try to stay inside the recommended range. It is possible on some GM applications to not have enough room to get to even the .100”. If this is the case, you may have to shim the actual transmission from the bell housing using washers or spacer. This is due to the shallow nature of the GM bell housing design. There are 3 shim thicknesses for the big 3. Mopar uses .063, GM uses .090 and Ford uses .057. The conical shape of the GM shims creates the .090 thickness, even though the metal used to create the shim is not that thick.


Bell facing to clutch diaphragm – minus Bearing Face to Trans bell face – minus .150 / .090 = Number of shims 


For example: Bell to diaphragm= 2.450, bearing to trans mount face= 2.125

2.450 – 2.125 – .150 / .090 = 1.94

This means your application needs 2 shims, which yields an air gap of .180”, which is perfectly acceptable.

For GM T56, Tremec Magnum, and Viper 6-speeds, American Powertrain recommends the following procedure for measurements:

Install the clutch and pressure plate to the flywheel on the engine. Place the straight edge across the fingers of the diaphragm and measure from the inside edge to the block mating surface. Record this measurement as A.

Next, install the Hydramax bearing retainer base with guide pin to the transmission and load the bearing onto the retainer, with the guide pin in position on the bearing. Install the bellhousing to the transmission. Place a straight edge across the bellhousing and measure to the bearing face. Record this measurement as B.

Using the formula below, calculate the number of shims. A block plate for a scattershield can be factored in by adding the thickness to measurement B.


B-A-.150 / .090 = # of shims


Once you have determined the number of shims, count them up and stack them behind the release bearing on the transmission shaft, install the bearing, and mate the engine to the transmission. It is that simple. Before you mate the trans to the engine, lube the o-ring on the inside of the bearing base with a little DOT 3 brake fluid.

To demonstrate the process, we installed a HydraMax hydraulic release bearing system on a GM LS- series engine with a Muncie 4-speed (mechanical linkage with an LS is not a simple proposition) which was being installed into a 1969 Chevelle. Setting up the bearing was simple, and the results yielded a smooth clutch without any hiccups.

The process begins by mounting the flywheel to the engine. We torqued the bolts to spec.

The clutch does not have to be installed if this is a mockup, but if it is the final install, make sure it is in there. Be sure to put the clutch in using the correct orientation.

Use an alignment tool to keep the clutch in position.

Next, the diaphragm is installed to the flywheel. There may be multiple bolt patterns on the flywheel, so you might have to find the right holes and line it up.

Use a couple of bolts to secure the bellhousing and then use a straight edge and ruler or caliper to measure the depth of the transmission mounting pad to the diaphragm fingers. Measure in 3 different places and note each measurement. This is measurement A.

The hydraulic release bearing mounts on a stud in the transmission. The American Powertrain kit comes with several studs to match the threads from the front bearing cover. Remove one bolt and match the threads.

Then the stud is installed into the transmission. Don’t forget to use medium threadlocker on the threads and bend the retaining tabs back over the hex on the stud.

The Hydramax bearing slides over the input shaft and locks in place on the stud, this is a free-floating unit, it does get bolted down.

Now measure the height of the release bearing to the transmission mounting flange. Make sure
that you measure to the top of the bearing. This is measurement B.

Using the formula, we determined we need 2 shims: (A – B)-.150”/.090 will determine the number of shims required. For example, 2.45-2.125- .150/.090 = 1.9 shims, so you use 2 shims. You can run as little gap as .100”, but .150 to .200 is optimum. Stack up the shims and install them behind the bearing.

At this point, the bellhousing is removed from the engine and bolted to the transmission using new grade 8 bolts.

Each hydraulic line threads onto the bearing and the line ran out of the bellhousing through the clutch fork hole. The lines are secured with a wire clamp.

Finally, the engine and trans are mated together and ready for installation in the vehicle.

Written By: Jefferson Bryant


Red Dirt Rodz
4518 Braxton Ln
Stillwater, OK 74074
405-880- 5343

American Powertrain
350 Transport Dr
Cookeville, TN 38506
1-931- 646-4836