Javelin engine and dogleg head development (research topic)

[Shadow Ahead]

Yes, other details that separate dogleg castings from rectangular castings, which I'm putting together photographically, will bear this out.

I would like to find out if there are further pictures of the engine bay from this series. It appears the original photographer used a lens filter which rendered parts of the same color as very dark, so dark that there are little to no detail features in the shadows despite using Photoshop and the like to pull those features up. The cylinder heads have markings that differentiate between dogleg and non-dogleg. Without the detail in the cylinder head shadows though, my conclusions will center entirely on the exhaust manifold details.

Steve

[Jon Mello]

Rare set of Javelin headers for sale on eBay for $1,749.99 buy-it-now.

https://www.ebay.com/itm/ORIGINAL-PENSKE-DONAHUE-AMC-JAVELIN-TRANS-AM-303-SHORT-DECK-HEADERS/112609669098?hash=item1a380f2fea:g:y6IAAOSwCJxZ6Ngq&vxp=mtr

[Shadow Ahead]

I have the whole group of photos from the Ebay sale saved. When it was posted on another forum by another AMC devotee I saved all the photos. I haven't had access to my computer since my wife and I moved and we are still organizing. However, before going into a more in depth study I can point out some immediate details that tie these headers to the ones in the black and white photos from the first page of this thread. The spigot shaped head at the top of the pipes. The seamed sections of each pipe. The numbering system on the spigots. These are definitely not Penske headers as described in the EBay ad. Penske race parts are marked with "RP", for Roger Penske. There are further characters that follow on Penske race parts from the era.
Back to the headers in the ad. I have the listing saved in "my EBay". If one looks at the 5th photo in the link, https://www.ebay.com/itm/ORIGINAL-PENSKE-DONAHUE-AMC-JAVELIN-TRANS-AM-303-SHORT-DECK-HEADERS/112609669098?hash=item1a380f2fea%3Ag%3Ay6IAAOSwCJxZ6Ngq&_nkw=penske+javelin&rt=nc&redirect=mobile, there is a number, "298", above the RD sequence in the same photo. A similar appearing raised set of marks are visible in the middle black and white photo on the previous page of this thread. The height of the markings are also in a very similar position relative to the safety wired bolts as the markings are positioned in photo 5 of the EBay ad. Also just visible in the b&w photo in this thread below the 3 digit number is the raised outline of at least one character below the 3 digit number, similar to the second row of characters seen in photo 5 of the ad. There are more photographic similarities between the ad and the black and white photo in this thread, but I will discuss that later.

Steve

[Shadow Ahead]

Correction - the 298 is actually part of the RD number sequence and upon closer inspection appears to be "293". Photo 5 in the ad is actually for the opposite side, the driver's side. Photos 1 and 2 are actually the same side as the middle black and white photo. The last b&w photo is the driver side, same as photo 5 in the ad. As stated before I will point out other comparisons between ad and photos posted here. My apologies for adding some confusion in my post earlier this evening.

Steve

[Shadow Ahead]

I can't take screen shots at this time. However if you look at the top EBay photo above (Jon's screenshot) either group shot of pipes, the lower middle pipe for the passenger side shows one pipe snaking under the other just like the second b&w photo shows. The b&w photo shows the outline of the R&D number on each head pipe ( evident in photo 2). The segments that each pie is made from are very evident in the top photo in Jon's screenshot and also evident in the b&w photo( number 2).
More to follow.

Steve

[Shadow Ahead]

Another easily identifiable feature is at the top of the first color picture - the long front pipe which would be part of the driver side pipes is also seen in the last b&w photo on the previous page of this thread. That picture is easy to pick out - the alternator is at the front. The long pipe starts at the front and is on top of all the other pipes. You can easily see its length as naturally it would be longest. It is also different than many other systems where the front pipe would go down at a much sharper angle and would then become more horizontal as it goes under the other pipes. Stahl and Douglass systems on small blocks come to mind with the more common layout I just described.
 The system where the pipes are brazed to the sectioned cast iron exhaust manifold outlets as seen in the black and whites of the Warren Prout Javelin cause the pipes to hug the block and the small diameter is also apparent. I can illustrate later how small the headers are when taking a set of measurements of my own AMC free flow manifolds. The small size would favor velocity and power as the manifold spigot conforms to the dogleg outlet much more faithfully than do headers and the gases are channeled at high speed into the straight pipe run without losing velocity. The Javelin design brings to mind the "zoomies" on old top fuel dragsters.

Steve

[PHAT69AMX]

Although "convention" is the 1970-Up AMC Exhaust Ports are known as "Dogleg Ports"
it appears to have been a mis-application of a descriptive term used in the 1970 ? SAE or AMA ? Papers
issued about the 1970 AMC 390 Engine... the phrase was used relative to the exhaust port ceiling...
No intention to buck convention, they'll always be known as Dogleg Port Heads...
The "significant" change, imho, made to the '70-up AMC Exhaust Port was to the Port Floor Contour...

Googled below Title, it's an 11-page SAE Doc, cover page says Mid-Year Meeting, May 20-24, 1968.
I have image files of 10 pages, but the 1st page is #'d page-14 ? and is titled:
"The American Motors AMX-390 V-8 Engine" ( 680493 )
by George F. Leydorf, Jr., Manager, Advanced Engine Design
and George E. Onishi, Manager, Development Department,
Advanced Engineering and Research ...

[Jon Mello]

Interesting information and thank you for sharing.  I had just assumed the dogleg reference had something to do with the little kickout in the lower right part of the port floor as seen in View A above.

[Shadow Ahead]

I'm very happy that Phat has joined the forum. His contributions  are typical of his "exhaustive " 😂 research.


Steve

[yenkomark]

  Not directly related to this topic, but I spent an hour with John Martin today , talking about American Motors and the Trans Am Javelins and his Rambler American A / Sedan

[crossboss]

FWIW,
Jay Cushman of Cushman Competition in Maine has a set (or sets) of those rare T/A headers.