Please help me build my 273
#979611
04/24/11 04:16 PM
04/24/11 04:16 PM
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Joined: Dec 2010
Posts: 11 las vegas
gmoritz625
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las vegas
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Hi guys. I have a 67 barracuda. Finished building a 340 for it but it has a funny vibration that shakes the car between about 2300-2800 rpm. I should have had the rotating assembly balanced. Anyway, I'm going rebuild a 273 right and save the 340 for a future product. I don't want to screw up designing this motor and am hoping for some help. I want to maximize performance. Car has 727 with 3.23 sure grip and 68 hi po exhaust manifolds. I have some 302 castings I was planning on using. Wanting to generate about 275 hp. Any comments appreciated.
Greg
Last edited by gmoritz625; 04/24/11 06:20 PM.
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Re: Please help me build my 273
[Re: gmoritz625]
#979613
04/24/11 06:29 PM
04/24/11 06:29 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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The OE 273 pins were very heavy (smaller ID) so that the smaller dia (therefore lighter) 273 pistons could be balanced the same to a 318 crank as heavier 318 pistons were. a person could use 318 pins since you are rebuilding/balancing from scratch but I think 273 pistons are not avail & even if they were the CR would b too low. Hughes may have something for you but depending on what head there may b a bore shrouding prob. Not much help to offer but wanted to kick things off for you
live every 24 hour block of time like it's your last day on earth
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Re: Please help me build my 273
[Re: gmoritz625]
#979616
04/24/11 10:06 PM
04/24/11 10:06 PM
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Joined: Nov 2009
Posts: 2,275 Desert Tracker
HYPER8oSoNic
top fuel
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top fuel
Joined: Nov 2009
Posts: 2,275
Desert Tracker
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The 4bbl pistons can be found at EGGE Machine Company (try egge.com) Look under Dodge 273 V8. This may help you, since the compression boost was in the pistons (domed type) and NOT the head. FWIW, it is a good build!! The 275 hp level you seek lies in the cam selection as well as compression.
"Stupidity is Ignorance on Steroids" "Yeah, it's hopped to over 160" (quote by Kowalski in the movie Vanishing Point 1970 - Cupid Productions)
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Re: Please help me build my 273
[Re: HYPER8oSoNic]
#979617
04/25/11 12:51 AM
04/25/11 12:51 AM
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Joined: Dec 2010
Posts: 11 las vegas
gmoritz625
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OP
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Joined: Dec 2010
Posts: 11
las vegas
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Quote:
The 4bbl pistons can be found at EGGE Machine Company (try egge.com) Look under Dodge 273 V8. This may help you, since the compression boost was in the pistons (domed type) and NOT the head. FWIW, it is a good build!! The 275 hp level you seek lies in the cam selection as well as compression.
what cam do you think? i think the 10.5 pistons with the 64cc heads would yield under 10:1 which would be perfect.
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Re: Please help me build my 273
[Re: gmoritz625]
#979618
04/25/11 10:20 AM
04/25/11 10:20 AM
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Joined: Jan 2003
Posts: 16,123 Grand Haven, MI
patrick
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I Live Here
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Grand Haven, MI
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tuck the 273 in a corner of your garage, and pick up a running, lower mileage 318 magnum. get an eddie RPM air gap for magnum motors. get some hughes #1110 springs and their retainers, and their camshaft snout extender to run a fuel pump with an LA timing cover. send the cam to Tim at bullet cams, get it reground with their HR259/316 lobe for both the intake and exhaust. if you tear down the motor to rering/regasket/rebearing, do the head porting mods Dulcich details in the may '05 issue of mopar muscle (biggies, opening up the pushrod pinch, and getting a good 5 angle valve job, and opening the VJ up to a 1.9" seat intake, 1.605" exhaust). run headers, and a 600 carb
will be a solid 300-320 HP an returned 18.6mpg with the last tank of gas in my 5th ave....
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Please help me build my 273
[Re: Baxter61]
#979620
04/25/11 05:06 PM
04/25/11 05:06 PM
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Joined: Jan 2003
Posts: 16,123 Grand Haven, MI
patrick
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I Live Here
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Quote:
I like that your going with the 273 and 340 to do something cool and be a little different than every other 360 and 318 out there. Use your 302 heads, do some minor porting, build your 273 shortblock and shove a solid roller in it. that would be cool and hit your hp goals.
yeah, a 273 is different, but unless you look at the castings #/engine stamping #, you'll never tell a 273 from a 318.
and you're giving up 45 cubic inches, which is a significant torque differential--rule of thumb, for a decently thought out street combo, 1.0-1.2 lb-ft per cubic inch is doable for peak torque.
stock 302 heads suck for flow potential, and without significant port work, will max out at about 250-270HP...
the 3.625" bore of a 273 will severely limit valve diameter and flow capability. the pistons will be much more expensive, to the point where you could buy new pistons and a 318 or 360 core motor....
there's a reason 318 and 360 builds are popular...because they make economic sense.
I love oddball stuff as much as the next person, I'd love to build up a hot slant 6, but I could never justify dropping serious coin on a seriously modded turbo slanty that would make as much power as a warm 318/360....
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Please help me build my 273
[Re: patrick]
#979621
04/25/11 05:24 PM
04/25/11 05:24 PM
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Joined: Feb 2003
Posts: 3,691 MO
cdp
master
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master
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Posts: 3,691
MO
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Seriously, for the $$ spent, why not find a good running 360 from a truck/van, add an aluminum intake, 340 manifolds, and mild cam, re-use the 360 converter and your 302 heads.
Around here, I've found several late 70's trucks/vans with good 318/360's for under 1000, most being in the $500 range. Sell whats left over for scrap.
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Re: Please help me build my 273
[Re: dan9]
#979624
04/26/11 11:20 AM
04/26/11 11:20 AM
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Joined: May 2003
Posts: 15,487 Florida
scratchnfotraction
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I Live Here
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Florida
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want a fast 273?? talk with the Rev member "class of 65" think his 273 still holds a record time slip,he has not posted in a while. that is one fast almost stock 273
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Re: Please help me build my 273
[Re: scratchnfotraction]
#979625
04/26/11 11:26 AM
04/26/11 11:26 AM
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Joined: May 2003
Posts: 15,487 Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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bumped an old 273 post back up for you to read might have some good info in there also,IIRC post "64 273 ?"
Last edited by scratchnfotraction; 04/26/11 11:27 AM.
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