1965 Offenhauser 273!

[65dartcharger]

When introducing the 273 in the model year it was first a two barrel carb at 180 hp. For the 1965 model year Chrysler introduced the 273 in two versions. A two barrel 273 still at 180 hp and then the new 273 four barrel engine. 235 hp, Carter AFB carb on a cast iron four barrel intake, hp camshaft, special valve covers in black wrinkle finish, crome breathers and a Prestolite distributor and they topped it of with a chrome air cleaner. Named Charger 273 for Dart and Commando 273 for Barracuda.
Frpm that on a lot of parts suppliers and manufacturrers of speed equipments start producing horse power stuff for the 273. Aluminium four barrel intakes were casted by Weiand, Edelbrock and Offenhauser.
Offenhauser and Chrysler started to cooperate producing high power stuff together as early as 1954.
In winter of early 1965 it seems like they took yp on that partnership. Chrysler built 40 1965 Dodge Dart with a special built 273 by Offenhauser.

So my intension is to build a copy of that engine. At the moment this is how it looks. Not exactly sure about the camshaft. Offenhauser is helping me on that.

 

[Plymouth 65]

Those valve covers and intake are vintage pieces, nicely done! 65'

 

[S'cuder]

I'm going to follow this thread.

 

[Syleng1]

If that is going in an early an under a stock hood; that will not fit under

the hood with all those carb spacers.
I have an offenhouser single plane correct for that time period with a 600cfm on my 273 and the air cleaner barely fits.

 

[Red0058]

i have one with a dual plane and the hood shuts. I think he has a chance.

 

[65dartcharger]

I spoked last night with Offenhauser who will give it a try to get more input.

Found a story in a motor magazine about a Dart Charger 273 built by the owner for drag racing. That decal on the front fender, could that Racer brown camshaft been added by Offenhauser.......? We'll see next week.

 

[Red0058]

Jim from Racer Brown had a member on here looking for an original D Dart cam shaft to put on their machine for specs. It was my belief the original D Dart camshaft came from Camcraft but the valve train springs may have come from Racer Brown. This may be apples and oranges info due to the Offy aspect. I will be tuned in to see what you find out. This is cool stuff thanks.

 

[mygasser]

If that is going in an early an under a stock hood; that will not fit underView attachment 1716254003 the hood with all those carb spacers.
I have an offenhouser single plane correct for that time period with a 600cfm on my 273 and the air cleaner barely fits.

what spacers? looks like the carb's bolted directly to the inlet to me.
neil.

 

[Syleng1]

what spacers? looks like the carb's bolted directly to the inlet to me.
neil.

I think you’re right. If you look at the carb the mounting looks like 3 horizontal lines like those are 1” spacers neatly put together. Better get my eyes tested.
Syleng1

 

[mygasser]

I think you’re right. If you look at the carb the mounting looks like 3 horizontal lines like those are 1” spacers neatly put together. Better get my eyes tested.
Syleng1

lol, are you looking on your phone? that won't help, i can't see **** on a screen that small even with my glasses on. that's why i have an old style nokia with buttons still.
neil.

 

[65dartcharger]

If that is going in an early an under a stock hood; that will not fit underView attachment 1716254003 the hood with all those carb spacers.
I have an offenhouser single plane correct for that time period with a 600cfm on my 273 and the air cleaner barely fits.

We'll see when we get to that point.

 

[65dartcharger]

Finally it was time for the paint, International red. I used a set of newer valve covers to cover the heads when painting the engine.
The black headers by some company will need a removed oil filter. @65 dart man, what supplier?
I just wish that Offenhauser would have some answer on the camshaft. So far Racer Brown or the Camcraft company is my guess.
Here is an ad from Walker Dodge in California about the D/Dart. You'll also see the 1965 Dart Charger 273 aka "Yellow Jacket"! Talk about a coincidence.

 

[72dustervs]

nice engine

 

[Red0058]

standby link malfunction...I can't get the link to copy and paste. The engine specs are online...if you do a small block mopar commando 273 275 horsepower d dart engine spec search they popped right up on my search engine

 

[65dartcharger]

Last night I talked to Offenhauser. They told me that the Offenhauser hi rise intake manifold added 18 hp and a dual 4 were 22 hp. Low rise aftermarket intake were 12 hp. They had no documentation left but they worked with camshaft manufacturers like Racer Brown, Edelbrock, Camcraft and Iskenderian.
During the 60ies they worked close with Bob Mosher with Chrysler V8s.
So is there any one who has contact info to him? Unfortunately he closed his shop Mosher Musclecar Restoration 2 years ago.

 

[ddartdude]

The Racer Brown cam in the Yellow-Jacket is an ST-14 with 0,486 lift. The Camcraft cam in the D/Dart had 0.501 lift. Both lifts mentioned are intake valve lifts.

 

[jeff alder]

https://www.motortrend.com/features/dodge-d-dart-273-december-1980-982-1244-77-1/

 

[65dartcharger]

Made a decision today. After going thru old carmagazines from late 64 and early/mid 1965 it seems like Chrysler mostly used the Racer Brown ST12 for mild street use and ST14 for mild racing. In the later part of 1965 they tested Camcraft that later becake the camshaft for the D/Dart.
So I called Jim at Racer Brown and ordered an ST14 camshaft. Next will be to figure out what carb and air cleaner they used.

 

[65 Cuda 340]

Interesting that the ST-15 cam has a lot more duration, but a lot less lift, than the ST-14.

When I overhauled my 65 Barracuda's original 273 back in 1971, I used a TRW solid lifter cam which, going by memory, was 284 duration, .426-.422 lift. Have no idea what the duration @.050 was, but at least on the surface, it appears to be quite similar to the ST-15 cam. It sure woke that little 273 up.

After I blew up the 273 in November 1972 trying to drive home to Cochran, GA from Charleston, SC in second gear (after I broke the 3-4 shift fork), I pulled the TRW cam out of the 273 and ran it in the 340 I had swapped into the Barracuda to replace the 273. The stock 340 cam would pump up the lifters if I overrevved it just a little bit in low gear, and it would be halfway through second before it fully recovered. The solid TRW fixed that problem, and made a little more power to boot.

 

[65 Cuda 340]

Those valve covers and intake are vintage pieces, nicely done! 65'

Actually, Offenhauser still makes the valve covers (or, at least they did the last time I checked). Maybe the intakes, too. Haven't checked them, but they still have the tooling for all sorts of their vintage speed equipment.

I have a recently manufactured set of them on my 65 and 67 Barracudas. I like them because I like finned aluminum valve covers, but also because they will accept the factory Commando 273 oil breather cap and pcv, and put them in the factory location.

 

[65dartcharger]

Actually, Offenhauser still makes the valve covers (or, at least they did the last time I checked). Maybe the intakes, too. Haven't checked them, but they still have the tooling for all sorts of their vintage speed equipment.

I have a recently manufactured set of them on my 65 and 67 Barracudas. I like them because I like finned aluminum valve covers, but also because they will accept the factory Commando 273 oil breather cap and pcv, and put them in the factory location.

View attachment 1716261304

Thanks for sharing.
I was wondering what pcv and breather cap they used. But since the cars arrived at Offenhauser with a 273 hp engine, it already had those items so that make sence. Re the red thermostat housing they just shifted it over to the aluminium intake manifold. So my guess is that the accelerator wire holder were moved over as wheel.
Hm, I like progress

 

[65 Cuda 340]

Well, here's a pic of the passenger side of the motor showing the pcv. It's a reproduction, not the factory original, but it looks the same.

 

[65 Cuda 340]

If that is going in an early an under a stock hood; that will not fit underView attachment 1716254003 the hood with all those carb spacers.
I have an offenhouser single plane correct for that time period with a 600cfm on my 273 and the air cleaner barely fits.

I run the same air cleaner on the slant six in my 63 Valiant. Offy intake, Edelbrock carb. It didn't quite clear the hood with the stock filter, so I used a shorter one with the same diameter (don't remember the part number). With the shorter filter inside the 273 air cleaner assembly, it cleared the hood. A bit less airflow, I suppose, but enough for my six.