273 Heads

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67's should be 920's and they are closed chamber. toolman
 
Thanks you guys.
I'm looking to increase my compresson to commando specs. 10.5
I'm also hearing that 10.5 compresson may be a little high for pump gas.
But if my heads are closed chamber I may be fine...
How am I doing so far?....
So is anyone running a 273 commando engine? If so, you still at 10.5? and how's she run?
Pistons apparently are gonna cost me a small furtune... so I gots lots o questions, eh. By time engine is back into the car I'm probly gonna run up to $2000. Pistons,rings n pins alone $1200 to $1500.

I'm thanking everybody for all and any input on this matter.
Thanks.
 
Under the valve cover is correct. The compression in the HP engines is in the pistons and yes they are near impossible to find. The rest of the build is plain old small block Mopar. I have a stock HP in my Dart and have no ping problems with 93 octane pump premium. I am planning a rebuild this winter. Now days,
$2000 isn't too bad for a rebuild. Good luck and keep us posted. toolmanmike
 
Yeah the numbers are on the #1 intake runner. As far as I know all 273 heads have a heart shaped buldge between the valves making them closed chamber.
 
Hey toolman,
the cost of $2000 is only to replace the pistons. The block and heads along with cam, lifters, springs, maifolds, carb. etc. was allready done just over a year ago.
 
That does seem a bit steep. If pistons are 5-$600 then the rest is machine time.
If you're using low compression pistons and machining for high compression results it takes a lot of grinding to get there. Egge and Flatlander has high compression pistons that don't require lots of machining for good results.
toolmanmike
 
Flatlander wants $749 + tax + shipping then convert to Canadian Currancy for a set of pistons and pins, no rings.
Also tried Vintage Auto parts - no stock available, (NOS).
 
Summit has low compression slugs for $280 a set
Hughes sells Egge high compression pistons for $472 a set
Kanter has some listed for $44.10 each
Egge has low and high compression pistons available (call 4 price)
Ross pistons can make what you want

The piston I posted above is a Egge off the Hughes website. It looks a lot like
the factory slugs. Egge also has complete engine kits or individual parts as needed. (rings, bearings, gaskets, cams, valve train parts, etc.)
I would check around for a competitive estimate from other machine shops in your area. I can think of 6 or7 reputable machine shops within
45 miles of my house. I'm sure your area is the same. Hope this helps.
toolman
 
I have my original 273 in my 67 Dart. Bored .060 over, 9 1/2:1 high compression pistons, 226/468 Comp cam (mechanical). I ported and polished the heads and a 550 cfm 4 brl. Timing is 12 degrees btc. My exhaust is an Emco 2 1/4 X pipe. I use 93 pump gas, no ping. Runs good. Pretty fast for such a small block. I just change out my 8 3/4 3.55 and installed 2.76. Not so quick off the line any more but will get up and go. I did not race it so I did not need a 3:55.

dave
 
#2658920 is a 1967 casting for the 273 and 318 engines. (first year for the LA-318). Closed chamber,5 valve cover bolts,1.78 intake valve,1.50 exhaust valve. late year production. There is no designation for the "6" on the end. toolman
 
Dave, I'd like to hear more about your build. That cam sounds like a good one for the 273. Do you have the Comp Cams number? Is the 550 cfm carb a Edelbrock? Is the Emco exhaust just the front pipe or a complete kit? Do you have any photos? toolman
 
Anyone try Layson's pistons? They list the HP pistons in all sizes (stock, 10 over, ...) for around $500 - $600 (if I remember correctly). Dave.
 
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