R3 Header question

[Avanti1963!]

I have what I think is a pair of unused R3 headers.  Three pictures are attached.  Please help to answer a few questions. 

-The left and right look exactly the same. 

-These don't have the alternator bracket sticking out of the front of the passenger side. 

-There is a part number 1558353 cast on the right horizontal face on each.   On the other front face is cast 206-86. 

-Pictures of the reproductions don't seem to have a number.

What do I have?  What models do these fit?  

Thanks

Edited January 18 by Avanti1963!

[mfg]

Not sure, but I’d guess you own the real McCoy… Amazing how, after all these years, rare parts like these still turn up !

[Nelson]

They appear to have been port matched. They certainly look original issue but I think the Lionel Stone versions were cast from the same tooling so I think those had the numbers also.

[Dwight FitzSimons]

Left & right exhaust manifolds ARE identical on ALL Studebaker Avantis, whether standard R1-R2 manifolds or R3-R4 "headers."  There was no need for a boss for an alternator bracket on Avanti manifolds.

Your R3-R4 manifolds will fit any Studebaker V8 from 1955 through 1964, whether 224, 259, 289, R1, R2, R3, or R4.

I have a set of Studebaker International's reproduction R3 headers and they have no numbers or letters cast into them, so yours are not the most recent repros. 

--Dwight

[mfg]

One of our Stude venders showed me a pair of R3 type exhaust headers cast in aluminum…. Not sure how that worked out.

[Gunslinger]

17 hours ago, Nelson said:

They appear to have been port matched. They certainly look original issue but I think the Lionel Stone versions were cast from the same tooling so I think those had the numbers also.

 

From what I've always understood Lionel Stone's repops showed a lot of flashing and required some work to get them to fit properly.  

[Gunslinger]

4 hours ago, mfg said:

One of our Stude venders showed me a pair of R3 type exhaust headers cast in aluminum…. Not sure how that worked out.

 

Back in the early '60s when Pontiac was a force on the drag strips...the days of their "Swiss cheese frames" to lighten the car...they also had aluminum headers.  Supposedly one could always tell when one of these cars made a run due to the molten aluminum drops on the track.  

[Dwight FitzSimons]

13 hours ago, mfg said:

One of our Stude venders showed me a pair of R3 type exhaust headers cast in aluminum…. Not sure how that worked out.

Dave Thibeault had some cast in aluminum a few years ago.  Dave generally does things well.

--Dwight

[64StudebakerAvanti]

Not sure aluminum is good material for exhaust manifolds.  According to sources on the internet, pure Aluminum melts around 1200°  with most alloys melting sooner. Exhaust manifolds can reach 1200° - 1800° under hard acceleration, extended high speed driving. Not much room for error.

[Nelson]

I’m not certain but StuV may have made the first set and that tooling could have been acquired by Studebaker or it may have been the other way around. I had or probably still have a set that has the name StuV cast into the header.

[A0136]

This is a set of reproduction headers I bought in the late 90’s early 2000. I haven’t cleaned the casting flash up yet. The other parts are a mounting bracket for the generator/ alternator.

 

[Zedman]

20 hours ago, 64StudebakerAvanti said:

Not sure aluminum is good material for exhaust manifolds.  According to sources on the internet, pure Aluminum melts around 1200°  with most alloys melting sooner. Exhaust manifolds can reach 1200° - 1800° under hard acceleration, extended high speed driving. Not much room for error.

Th Coefficient of thermal expansion for Aluminium/alloys is around 0.0008" per degree Celcius - That's nearly a thou every degree.  From that standpoint I'd wonder whether Stress cracking would be a valid problem.

[64Avanti]

On 1/19/2026 at 4:11 PM, Gunslinger said:

 

From what I've always understood Lionel Stone's repops showed a lot of flashing and required some work to get them to fit properly.  

The ones that Lionel Stone had cast used the original tooling.  They were somewhat difficult to get good castings.  When we used that tooling back around 1972 the foundry had to scrap about 20% of them.