273 commando Build

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Jon
The factory 273 hipo engine, I have the heads off, in my garage, had steel shim head gaskets. I still have the gaskets. I will mic them later, and post my measurements.
Dave
 
stroker402 said:
Toolmanmike and others can you answer this question >>>>>>>>>>>>>>>>>>>>>>>
Are steel shim head gaskets made of embossed steel like they are described as or are they made with a composite material like felpros?
I've seen a pair on the internet saying they were the steel shim gaskets but they looked like they were composite like felpros. this image is for a 273 head gasket and it does not look like a steel shim gasket at all . what gives?
maybe some you have torn apart these engine over the years can tell us what is suppose to be installed from the factory , steel metal shim or composite ?

View attachment 1715160940
Click to expand...
A steel shim gasket is exactly that, a flat piece of thin steel stamped on a set of dies to emboss it to the designed shape. The gasket you pictured would be considered a composite gasket although fairly thin. I used the silver colored composite gaskets on my 273 and so far, after many years, are doing fine. You will loose a bit of compression, I am guessing a half point possibly, but you don't want to build a engine and not have it pump gas friendly. 9.5/1 is a good number with cast heads.
 
As I mentioned earlier, I don't believe steel shim small block gaskets have been made for decades. Here's Summit's list of head gaskets. There is 1 with a .038 compressed thickness and many with a .039 and .040 compressed thickness. They are also listed for bore size and you will want to get as small as you can and still stay thin. The bore sizes are designed to fit 318-340-360 bores. The only other option is to contact Cometic and have them make a small bore MLS (multi layer steel) gasket. They aren't necessarily thin though like the old steel shim's were. (usually around .020)

DODGE 4.5L/273 MOPAR SMALL BLOCK LA Head Gaskets
 
barracudadave67 said:
Jon
The factory 273 hipo engine, I have the heads off, in my garage, had steel shim head gaskets. I still have the gaskets. I will mic them later, and post my measurements.
Dave
Click to expand...

Thanks Dave ! I wonder now what the picture I posted is .
 
Jon
Here is a pic of the steel shim gaskets, for the 273 HP. They mic out at .0245-.025, This is on one, or two of the clean spots. The center tab has a PN of 2536757, and the right tab has a# of mc 6681, verticlaly, on it.Hope this helps.

20180404_140202 (640x360).jpg


20180404_140202 (640x360).jpg
 
20180404_150529 (640x360).jpg
20180404_150622 (640x360).jpg

Heres pics of how the gaskets fit. You can see they are not round, as the cylinders. Their is roughly a 1/8th in gap all the way around, except for the extreme top of cylinder, and the gap is wider at the center of the cylinder. I measured them with a vernier, and as close as I could get. Vetically they measure 3.963 in, and horizontally they are 3.763 in, that is at the wide point.
One pic is with out gasket, the other is with gasket.
Dave
 
barracudadave67 said:
Jon
Here is a pic of the steel shim gaskets, for the 273 HP. They mic out at .0245-.025, This is on one, or two of the clean spots. The center tab has a PN of 2536757, and the right tab has a# of mc 6681, verticlaly, on it.Hope this helps.

View attachment 1715161028


View attachment 1715161027
Click to expand...
barracudadave67 said:
View attachment 1715161039 View attachment 1715161040
Heres pics of how the gaskets fit. You can see they are not round, as the cylinders. Their is roughly a 1/8th in gap all the way around, except for the extreme top of cylinder, and the gap is wider at the center of the cylinder. I measured them with a vernier, and as close as I could get. Vetically they measure 3.963 in, and horizontally they are 3.763 in, that is at the wide point.
One pic is with out gasket, the other is with gasket.
Dave
Click to expand...
Geeeeeeeeee ! They look distorted ! I never seen anything like that . doesn't look right at all. Thanks Dave for the pics !!
ps: can't find these part numbers anywhere on the net.
 
I looked the head gasket up in a late 60's parts book. The original 273 part number was #2463338. I checked here on FABO and a thread concerning that head gasket. I see 69 Cuda 440 lists this gasket in his post. Dave's head gaskets are probably a later service part. (the later part number tells us that) I would imagine the "distorted" shape is for larger bores on other engines. Looks like that is where the valves are. The hottest part of the chamber is around the exhaust valve. These gaskets can be used on either cylinder and Mopar's exhaust valves aren't all on the same side of the chamber. Keep the fire ring away from the direct heat.
Commando Cylinder Head Gaskets 273 1967
 
The embossed mic'd at <.020? Man the ones I took out were paper thin. Must have been an illusion. I bet Mopar saving a buck on these stamped shim gaskets bit them in the *** in warranty work so they ended up putting standard gaskets on later years.
I am questioning Galens 1.87 intake valve size of the 66 D-Dart/273-4 CAP (clean air package!!!) program as I just dont see it anywhere in the literature.

Here is a quote from a Paul Canizzaro
"I worked for Chrysler from 1964 thru 1969. I worked with the Special Performance Group, under the direction of Dick Maxwell and Tom Hoover. I worked on and helped prepare the 1966 D-Darts during the spring of 1966.
...we could not install larger valves in the heads without serious modification (notching of the block).

....at about the same time, the Muesers ran a 12.78 with their Corvette. That time was not achievable with our 273, and we knew it. Right then and there, the D/Dart program was basically over. ...
So we prepared a water-downed version of
the D-Dart, nowhere what it was supposed to be. .. The cam would add about 20 horsepower over a stock unit. ... In reality, it was a cheap way to increase horsepower, In fact the engine only put out about 255 horsepower, which would have put the car in F/Stock, and would have been more competitive. The only reason the headers were installed (to add about 15 to 20 horsepower),
was that we had already purchased the units. It was really fake horsepower...
...We argued that we should not produce a half-baked project, but somebody up there in the head office wanted the cars out there. Really it was cover your butt project. Though there are claims that 50 cars were produced in April of 66', the truth is about 25 or so were
built. To this day, I have only seen (2) D-Darts race. I have never seen a true D-Dart at any Mopar meets...

now if the member here that has 2 D-Darts can put to rest this 1.87 valve issue, Ill sleep better tonight. Curiously, the 1.87 figure is the valve center to center of all LA heads.....and its also a dyslexic 1.78. I wonder if something got screwed up in translation?
 
pishta said:
The embossed mic'd at <.020? Man the ones I took out were paper thin. Must have been an illusion. I bet Mopar saving a buck on these stamped shim gaskets bit them in the *** in warranty work so they ended up putting standard gaskets on later years.
I am questioning Galens 1.87 intake valve size of the 66 D-Dart/273-4 CAP (clean air package!!!) program as I just dont see it anywhere in the literature.

Here is a quote from a Paul Canizzaro
"I worked for Chrysler from 1964 thru 1969. I worked with the Special Performance Group, under the direction of Dick Maxwell and Tom Hoover. I worked on and helped prepare the 1966 D-Darts during the spring of 1966.
...we could not install larger valves in the heads without serious modification (notching of the block).

....at about the same time, the Muesers ran a 12.78 with their Corvette. That time was not achievable with our 273, and we knew it. Right then and there, the D/Dart program was basically over. ...
So we prepared a water-downed version of
the D-Dart, nowhere what it was supposed to be. .. The cam would add about 20 horsepower over a stock unit. ... In reality, it was a cheap way to increase horsepower, In fact the engine only put out about 255 horsepower, which would have put the car in F/Stock, and would have been more competitive. The only reason the headers were installed (to add about 15 to 20 horsepower),
was that we had already purchased the units. It was really fake horsepower...
...We argued that we should not produce a half-baked project, but somebody up there in the head office wanted the cars out there. Really it was cover your butt project. Though there are claims that 50 cars were produced in April of 66', the truth is about 25 or so were
built. To this day, I have only seen (2) D-Darts race. I have never seen a true D-Dart at any Mopar meets...

now if the member here that has 2 D-Darts can put to rest this 1.87 valve issue, Ill sleep better tonight. Curiously, the 1.87 figure is the valve center to center of all LA heads.....and its also a dyslexic 1.78. I wonder if something got screwed up in translation?
Click to expand...
Man I miss this guy. (RIP Paul)
 
pishta said:
The embossed mic'd at <.020? Man the ones I took out were paper thin. Must have been an illusion. I bet Mopar saving a buck on these stamped shim gaskets bit them in the *** in warranty work so they ended up putting standard gaskets on later years.
I am questioning Galens 1.87 intake valve size of the 66 D-Dart/273-4 CAP (clean air package!!!) program as I just dont see it anywhere in the literature.

Here is a quote from a Paul Canizzaro
"I worked for Chrysler from 1964 thru 1969. I worked with the Special Performance Group, under the direction of Dick Maxwell and Tom Hoover. I worked on and helped prepare the 1966 D-Darts during the spring of 1966.
...we could not install larger valves in the heads without serious modification (notching of the block).

....at about the same time, the Muesers ran a 12.78 with their Corvette. That time was not achievable with our 273, and we knew it. Right then and there, the D/Dart program was basically over. ...
So we prepared a water-downed version of
the D-Dart, nowhere what it was supposed to be. .. The cam would add about 20 horsepower over a stock unit. ... In reality, it was a cheap way to increase horsepower, In fact the engine only put out about 255 horsepower, which would have put the car in F/Stock, and would have been more competitive. The only reason the headers were installed (to add about 15 to 20 horsepower),
was that we had already purchased the units. It was really fake horsepower...
...We argued that we should not produce a half-baked project, but somebody up there in the head office wanted the cars out there. Really it was cover your butt project. Though there are claims that 50 cars were produced in April of 66', the truth is about 25 or so were
built. To this day, I have only seen (2) D-Darts race. I have never seen a true D-Dart at any Mopar meets...

now if the member here that has 2 D-Darts can put to rest this 1.87 valve issue, Ill sleep better tonight. Curiously, the 1.87 figure is the valve center to center of all LA heads.....and its also a dyslexic 1.78. I wonder if something got screwed up in translation?
Click to expand...
Could very well be.
 
Tool man mentioned the probability of the gaskets I pictured as having been used in a repair. I think, also that is correct, as the engine had two differently numbered heads on it. The one # is 2465315, the other head I sold to Jon, and don't remember the #. So I think it had some engine work at one time. It was out of a 66 B-Cuda Formula S 4 spd w/ 8 3/4 rear, that I scrapped out in 2015.
Don't know why they miced out at .025, if the gaskets were supposed to be .020.
Dave
 
Checking the rod and main bearings to see how they look. Everything looks great ! NICE Crank ! can anyone decode the numbers on the bearings for me . Look to be all standard mopar bearings . here are 2 pics of the rod and main bearing numbers . the 466 number is the mains . Going to order up new rod and main bearings along with piston rings .

IMG_6406.JPG


IMG_6407.JPG
 
stroker402 said:
You are correct , I just measured the the size of ld340 ports vs my 920 intake port size and they are a mismatch.
Click to expand...
That's not a deal breaker. Putting 340/360 size port intake on 273/318 size port head is ok. I've done it a ton, and always have had great results.
 
318willrun said:
That's not a deal breaker. Putting 340/360 size port intake on 273/318 size port head is ok. I've done it a ton, and always have had great results.
Click to expand...
most people say the larger intake port ld340 is not good on 273-318 ports . It hurts the velocity flow. Air /fuel mixture is not moving like it would with the correct port diameters . So they say !
 
stroker402 said:
most people say the larger intake port ld340 is not good on 273-318 ports . It hurts the velocity flow. Air /fuel mixture is not moving like it would with the correct port diameters . So they say !
Click to expand...
of course it's better to have perfect alignment. However, the air is being "pulled" into the head by the piston instead of being "pushed" into the head. I've done this so many times, and never had a bad experience. In fact, i just pulled a factory cast 340 intake off my 318 with 318 heads, and installed a Holley SD intake with 318 ports. So far, the cast has run almost tenth faster and more mph. I'm going to work with it a little more, then perhaps try another intake .... all for funs.
 
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