I can't remember the brand. I got them from Egge I believe.
Building a 273
- Thread starter 273Dynamite
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pishta
I know I'm right....
All seem very pricey. Another reason to build a 318.....:-(
Sealed Power for $57. 1966 DODGE DART 4.5L 273cid V8 Piston Ring | RockAuto
JDMopar
Well-Known Member
I'm using Total Seal. Modern style ring pack with thinner top and 2nd rings. They ain't cheap, but will work well for the type motor I'm building. 65 block I got from a member here, .030 over with forged flat tops at zero deck, Bullet hydraulic roller with .447 lift on both sides, 302 heads with 1.88 intake valves and a little pocket porting. Gonna flip a coin on a Weiand 8007 and an Edelbrock D4B. MP ignition, and Dougs D450's. Not too wild of a motor, but enough to make my 65 Barracuda get out of its own way!
Beams
Well-Known Member
Out of curiosity, are you planning on modifying the D4B to work with the 302 heads?I'm using Total Seal. Modern style ring pack with thinner top and 2nd rings. They ain't cheap, but will work well for the type motor I'm building. 65 block I got from a member here, .030 over with forged flat tops at zero deck, Bullet hydraulic roller with .447 lift on both sides, 302 heads with 1.88 intake valves and a little pocket porting. Gonna flip a coin on a Weiand 8007 and an Edelbrock D4B. MP ignition, and Dougs D450's. Not too wild of a motor, but enough to make my 65 Barracuda get out of its own way!
MOPAROFFICIAL
Oogliboogli
The 273 is a fine Little Engine but if you want the power you're aiming for you could do it easier with a bigger bore like a 318 and no one would ever know it was a 318 cuz the block dimensionally is the same size outside of the cylinder bore...n why not a 360, because the 318 blocks can be had for free many times as are the 273's. The iron intake as far as airflow goes is utterly a pos and heavy. Get a dual plane intake for better low end power and all around better performance. As for what heads to use if you go to 302 heads and don't just use the 273 head which is already a good head you'll find you need a specific amount of work and it's not cheap to make that head perform to its potential. You could just as easily have your closed chamber 273 heads worked and do a little bowl blending to them and way less chamber massaging and be done and have a great flowing head for what it is. Now in regards to heads and power in general...if you were to go to a 318 bore you would open the door to a magnum head which flows way better than all of those little heads including the 302 and then your power goal will be there and then some. Only catch is you need to figure this out before you start buying intake manifolds ,pistons and all this other crap.
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JDMopar
Well-Known Member
If I end up using that one, it won't need to be modified. I had it on a 318 in a 71 Challenger years ago and it fit just fine. The bolt holes got ratted out enough to fit way before I ever got it. I'm leaning more towards the Weiand anyway, because it's a spread bore intake and I'm probably gonna use a 72 Thermoquad I got from @GTX JOHN .
Either Speed Pro, Original Chrysler, or Total Seal.
You're doing nothing but leaving torque and power on the table, messing with the 273. For what you'll spend on the 273 reciprocating assembly you could easily buy a 360 stroker crank and pistons and build a 408. Better yet do it to a late model magnum engine. You'll end up with a 400-450 HP engine instead of a (maybe) 300 HP engine. You can then just tell people it's a 273 
You're doing nothing but leaving torque and power on the table, messing with the 273. For what you'll spend on the 273 reciprocating assembly you could easily buy a 360 stroker crank and pistons and build a 408. Better yet do it to a late model magnum engine. You'll end up with a 400-450 HP engine instead of a (maybe) 300 HP engine. You can then just tell people it's a 273
I never cared for a 360, scrapped or sold all I had. I don't need to spend the money for a stroker anything to go fast. Another answer to a question never asked. Put a stupid 360 in it...
Hmmm. Ok, to each his own
RandyB
Well-Known Member
I am really thinking of putting a 360 magnum from a 1997 Ram into my 65 Barracuda. Add a comp cam and headersYou're doing nothing but leaving torque and power on the table, messing with the 273. For what you'll spend on the 273 reciprocating assembly you could easily buy a 360 stroker crank and pistons and build a 408. Better yet do it to a late model magnum engine. You'll end up with a 400-450 HP engine instead of a (maybe) 300 HP engine. You can then just tell people it's a 273
Dan the man
Well-Known Member
A 318 would not only be cheaper to build but would be easier to get the power that you are looking for.
Can you post part numbers for the pistons and rings? Only pistons and rings I can find are from Egge.I'm using Total Seal. Modern style ring pack with thinner top and 2nd rings. They ain't cheap, but will work well for the type motor I'm building. 65 block I got from a member here, .030 over with forged flat tops at zero deck, Bullet hydraulic roller with .447 lift on both sides, 302 heads with 1.88 intake valves and a little pocket porting. Gonna flip a coin on a Weiand 8007 and an Edelbrock D4B. MP ignition, and Dougs D450's. Not too wild of a motor, but enough to make my 65 Barracuda get out of its own way!
Their pistons are L2222. Their online catalog is a pdf so it is a little hard to navigate.
JDMopar
Well-Known Member
The pics that @66fs posted are what I used. They are custom forged pistons from Race Tec. As of right now, there are only 3 sets of them in the world. My two sets and Dan's set.
I have the ring box with the part number at home. I'm at the beach right now, or I'd post a pic of the ring box. They were customs from Total Seal. If you decide to get some of the Race Tec pistons like ours, shoot me a PM after you order them and I will give you the part and order numbers for the rings.
Thanks. Definitely going to call them this week, but my family CFO says I have to wait until after New Years to order them.The pics that @66fs posted are what I used. They are custom forged pistons from Race Tec. As of right now, there are only 3 sets of them in the world. My two sets and Dan's set.
I have the ring box with the part number at home. I'm at the beach right now, or I'd post a pic of the ring box. They were customs from Total Seal. If you decide to get some of the Race Tec pistons like ours, shoot me a PM after you order them and I will give you the part and order numbers for the rings.
'65 S
Active Member
You probably have this info already but just in case I'll post them. When I inherited my uncles '65 Formula S I also got all his Hot Rod magazines (complete up to '74 or so) and a lot of white paper from MOPAR. Clearly he was going to drag race the car, obvious by all the paperwork he'd collected. every now and then I check in to read up on the 273 as I'm going to rebuild with the original 27, 000 mile engine or the '66 S engine that he had stashed in his barn. Always learn something here as I'm more into old Fords and Chevys.
By the way, somewhere in this paperwork I've seen the term Super Commando 273 used but can't find it right this second but I did remember this formula for the 275 hp version.
Good luck!
we're pretty close, I'm in Long Beach and my aunt lives in San Pedro.
Sorry for the phone pics, my scanner took a dump.
Babyblue66
Cool dude
I did a 273 for my 65 barracuda in 2009. It had new pistons in it already when I got it. They came out to 7.8 to 1 with a fel pro gasket. I worked at a shop so I cut 40 off the heads and 45 off the block to get 8.9. I didn't have much money, but I shouldve just bought egge pistons. Better yet, I should've just put a 360 in it. It still runs great with a small solid cam and a stock 65 4 barrel intake. But it's definitely not fast. With 3.55 gears in it, it was better, but still wouldn't burn both tires. It's a nice little cruiser though, needs to be above 3k rpm for any torque.
Anyone seen or heard from @273Dynamite since August?
bigrobsRT
Well-Known Member
dibbons
Well-Known Member
I believe the factory Commando 273 pistons provide a higher compression than the currently available Egge piston replacement. Either a shorter dome or a varied piston pin height would be the reason. I ran the TRW forged Commando piston replacements (I used .060 overbore which works out to 282 cubic inches) back in the '70's which advertised the same factory 10.5:1 compression rating. Base on E.T. and MPH on the quarter mile (12.72 @ 108 and 3150# with driver) the horsepower works out to be about 305. Edit: 4.56 rear end
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If I was to build a 273 would use 4.10 as a minimum, smaller engine need more gear,
running 3.55 behind a 273 is like running 2.76 behind a 360, 3.55 is a compromised gearing for a 360 a 273 would need 4.56 to have similar torque to the ground as a similar powered 360.
Why one of my signature tagline is "If your willing to gear it build it if not build a larger displacement, Or take solace in your compromises."
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