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Avanti Performance Upgrades


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Greetings to all. My brothers and I are in the process of rebuilding my Dad's 64 Avanti. We have rebuilt the R1 engine, rebuilt the rear Twin Traction axle and put stock 3.31 ring and pinion back in it (someone had changed it to a 4.11), and had the automatic transmission rebuilt. We had the body taken off the frame, the frame sand blasted, repaired and painted. We also had the paint stripped off the fiberglass body and had the body repainted with the proper Avanti Red color. We still need to rebuild the HVAC system and refurbish the interior.

Our goal has been to keep the stock look of the Avanti while making performance upgrades. For instance, we used the Turner disc brake kit in the front to replace the stock Studebaker disc brakes. It was a significant improvement in stopping power and heat dissipation. The engine was kept stock except for the .030 over pistons. So, what I am looking for is input.

Does anyone have information on good performance upgrades to make to the Avanti to improve its driveability and safety? This car is not going to be a garage or trailer queen. We are going to drive it a lot. At some point, I would like to take my Dad on a cross country trip in this car. (Although right now I am sitting in Iraq with the 153rd Field Artillery, so I am not driving it at all.) I already have a line on one possible improvement: dual chamber master cylinder. Some things I know I want to explore are changing the two piece rear axles to the one piece design (I don't have much info about that), converting to rear disc brakes (I don't have any info about that), and using wider wheels and wider tires for better handling (I have found a decent amount of info about that).

In return I am more than happy to share with the group any information that I have learned during the ongoing rebuilding process. I personally disassembled and reassembled the engine. I also personally rebuilt the Power Lok (Twin Traction) differential with a new clutch pack, set up the new ring and pinion gears and replaced all of the bearings and seals in the Dana 44 rear axle. So, I know a decent amount about the engine and rear axle. The other stuff I observed, but am still willing to share anything I know.

Sorry I don't have pictures here with me in Iraq, but I will ask my family to email me some of them so that I can post them.

Thank you (yeah, I know it's a long post).

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First...thank you for your service to America. You are well appreciated and your well being is a big concern for all of us.

You've already identified a lot of good upgrades...the brakes, dual master cylinder, etc. There are a few other performance upgrades to consider, though they will add some considerable expense but I think they're worth considering.

Instead of the stock cast iron intake manifold, you might try and locate an original Offenhauser aluminum 4 barrel intake..I see them occasionally on Ebay and big swap meets they show up. These are better than the stock Stude unit and being aluminum it weighs less and sheds heat faster. I also understand you can take an intake made for the small block Mopar and it can be adapted to work, but I have not seen them myself. I believe a Stude enthusiast has made adapters to accomplish this.

If you change the intake, get a new Edelbrock Performer carburetor...it's an updated clone of the original Carter AFB and is an excellent unit to use. Another advantage of the Edelbrock is the linkages should hook up without modification. Actually, one of the best street carbs ever is the Rochester Quadrajet, but they're no longer made and even good rebuilds are expensive, plus you would need an adapter to use it with a square bore intake as it is a spread bore design. By changing the carburetor, you would likely need a new air cleaner as the diameter of the carb's opening is a good bit more than the original AFB. You can use a modern air cleaner base and still use the original chrome aire cleaner lid. Also get a low restriction K&N air filter element or equivalent.

Something else to consider is to have a good radiator shop build you an aluminum radiator assembly...one with as many cooling fins per inch as possible. Your original radiator is likely not up to standards anymore and a new aluminum core will transfer heat more rapidly and save some weight on the front end of the car. Avanti's are nose heavy to begin with, so a weight savings and increased cooling efficiency is a no brainer in my view if you're not interested in a completely stock museum piece. Take advantage of new technology.

For the interior, I'm assuming you're going to install new carpeting. Get a good heat insulator on the floor and firewall before installing the carpeting. Corvette specialty catalogs carry the stuff and it will keep heat out of the interior. If you're not concerned about originality, consider replacing the stock gauges with new one's from Auto Meter, VDO, or Stewart Warner. Besides a more modern appearance, they will be more reliable and accurate. The original gauges Stude used weren't all that accurate...read reviews from when the Avanti was first introduced and many mentioned how the speedometer and tach were inaccurate. It's difficult to rebuild the original tach sending unit and almost impossible to find a replacement these days anyway.

If your car is air conditioned, you might get a new Sanden compressor...smaller, lighter and more efficient than the original York or Eaton compressor, plus it's designed for the current R-134A refrigerant rather than the old R-12. While you have the car apart, go ahead and upgrade everything you can.

You can also install the quick steering arms available. A good improvement.

Most of what I've mentioned will add considerably to your costs, no question. It will also make for a much more responsive and comfortable car as well. I'm sure others have ideas as well to consider.

Hope these ideas are useful to you. Stay safe and get the job done.

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Similar question....Gunslinger & others...

I also have a new 63 R1 and I'm considering a few upgrades (the car's in good shape so a full restoration isn't planned...for now) like the AC conversion, but I do want to keep it as stock looking as possible. I figure if I really wanted seriously upgraded performance and modern features, I would have bought an Avanti II and not worry about originality. Still, my new equivelent of the Avanti has me spoiled and reliability is a big issue with me.

You mention the quick steering arms...what about bigger anti-roll bars?

Also, does the dual master cylinder mod look stock? Does any one make a rear disk kit?

Thanks, John

DADAVANTI....let me echo Gunslinger's comments...thanks for your service and hope all of you have a great holiday season. Take care & God bless.

Edited by J Boyle
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A dual master cylinder would not look stock, but would look normal to anyone not familiar with older cars and single master cylinders. I believe the dual master cylinder used on Avanti II's was a contemporary Mopar unit. I'm sure someone else here knows the proper application if I'm wrong.

I remember years ago you could buy anti-roll bars through JC Whitney...I believe they were ADDCO units and maybe they still have them even if they don't list them anymore. They may fit other makes as well but I remember they listed them for Studes and Avanti's. Avanti came with them originally so I don't know if they were an identical replacement or an upgrade. For all I know ADDCO may have been the original supplier for Stude anyway.

There have been a few people who have installed rear disc brakes on Avanti's, but I don't know if it's a completely engineered kit that's available or someone took it upon themselves to experiment. I wish I knew more about it but again, hopefully, someone else here may have better information.

To my way of thinking, there is only so much one can do with the old Stude chassis to upgrade it. It may be strong, but it's old technology and no one is in the business of making high performance Studebaker parts...be it chassis, suspension or drive train. Most of what's out there is geared toward restoration. Most improvements are adaptions of current technology, though there is the upgraded disc brake kits for the front. When there were only 4643 Stude Avanti's made, and even fewer Avanti II's on the Stude chassis, it simply doesn't make sense for a performance company to invest big bucks into developing performance parts for such a miniscule market. The enthusiasts who own the cars do it themselves by trying different things...many just one-off experiments or custom shops that will do it for an owner for big money.

You can do some standard hot rod tricks, better tires, adapt modern technology to the cars and chassis, but that's really the extent of what's reasonable. You also have to keep in mind that many changes in any car's suspension and chassis can upset the car's center of gravity, handling, etc., in a negative way and make for an unsafe vehicle. At low speeds and gentle driving it may make little difference, but ramp up the speed and certain road conditions the car can then bite you in a hurry. See what happens to some of the SUV's that have been equipped with oversize tires and rims and how many end up rolled over or off the road because the changes were beyond the vehicle's design envelope. Not to say you can't make changes, but to gain something you necessarily have to give up something. You want to improve safety and performance, not sacrifice it. If you have to sacrifice something to gain what you want, make it nothing more than work, sweat and as little money as necessary to accomplish it.

I'm off my soapbox now.

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The engine was kept stock except for the .030 over pistons.  So, what I am looking for is input.

There is a LOT of improvement to be had from porting the stock Stude heads, if

you also go with 1.94 intake valve you will be amazed at the difference in power.

Some things I know I want to explore are changing the two piece rear axles to the one piece design (I don't have much info about that)


converting to rear disc brakes (I don't have any info about that)

Dave at Steeltech makes them:


using wider wheels and wider tires for better handling (I have found a decent amount of info about that).

See my thread on here about what I am running.


Edited by SBCA96
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