273 or NOT 273?

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NC Engine Builder said:
Not a bad recipe, but I'd either do a magnum head, or a 340/360 casting. The 318 casting lacks enough port cross section imo. And nothing is truly exotic about it, but if I were doing it, I would have a custom piston made for it, chevy pin diameter, and a metric ring package. The ring package alone is reason enough to go custom. With that, you can turn your 273 crankshaft rod journal to the generic "chevy" size, and have a much better selection of shelf rods, in numerous lengths. Allows you to shorten up the excessively tall compression height of the factory type pistons
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this is answer right here.

in a game of "ounces add up to pounds" you want to take every advantage you can. a modern ring pack can be worth as much as 10hp and that number only gets better with a smaller, lighter piston with the advantage of better compression height.

if i was headed this direction i'd know two things off the bat: 1, it's going to be more $ per hp than anything else small block; and B the only things "273" left would likely be the block and the crank.
 
67_Slimer said:
So no matter what I get out of this post , at least I know I'm "pathetic"
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naw, not what he meant. My Duster runs 12's and the number "12" by itself isn't fast by todays standards as you know, however, to your point a simple old school back yard build with small cubes is impressive running that number.
"It's not how fast you go, but how you go fast..." :)
 
273 said:

This is I think P.I.E build​

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​

The 273 Build That Doesn't Suck​

Forget The Little Engine That Could. This Is The Little Engine That Does!
WARNING: Reading this article might cause you to giggle uncontrollably with excitement. It might lead to sleepless nights and neglected work-hours spent planning your own 273 build. It might have you scrounging vintage salvage yards, the classifieds and maybe even strangers' back yards looking for neglected 273 cores. It might even lead you to abandon all rational engine building protocol in the quest to create your own dare-to-be-different scream machine.
We are not responsible for any of this. However, if you choose to build an engine like this, we'll be right there to help you build it.
A few months ago, Chris Sockriter stops into our shop with that glint in his eye and a plan in his head to build a hot 273 for his 69 Dodge Dart. Now if this was 1965 and the
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~previous message edited for brevity~

you've posted this before, and to my knowledge there wasn't a dyno sheet attached. 360/355 is stout for a "273" and i wonder at what RPM...

anyway, call me suspicious... but those numbers with a 700cfm carb and a 218/226 @ .050, .525 114 LSA cam? *narrows eyes*
 
I'd go Magnum replacements and a mild port job, gives a closed chamber too but a better port than 302.
 
junkyardhero said:
~previous message edited for brevity~

you've posted this before, and to my knowledge there wasn't a dyno sheet attached.
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A dyno graph would of been nice.
junkyardhero said:
360/355 is stout for a "273" and i wonder at what RPM...
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355 lbs-ft x 90% = 320 lbs-ft, 360 hp x 5252 / 320 lbs-ft = 5,910 rpm.
My guesstimation 360 hp around 5,900 rpm.
junkyardhero said:
anyway, call me suspicious... but those numbers with a 700cfm carb and a 218/226 @ .050, .525 114 LSA cam? *narrows eyes*
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I could see that, but a decent ported set of magnum's shouldn't need too much cam to make 360 hp, Richard Holdener gets similar hp out of a stock Magnum and similar cam. But be nice to see dyno evidence.
 
junkyardhero said:
~previous message edited for brevity~

you've posted this before, and to my knowledge there wasn't a dyno sheet attached. 360/355 is stout for a "273" and i wonder at what RPM...

anyway, call me suspicious... but those numbers with a 700cfm carb and a 218/226 @ .050, .525 114 LSA cam? *narrows eyes*
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Isn't that shop pretty famous for "BS" ???
 
318willrun said:
I just posted the 302 remark because I know Newbomb loves them :D
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Not like there a terrible choice, it's probably the one application there a decent choice for, If the OP is great at porting and has a bench etc.. A set of 302's might be the ticket. but I'd still go magnum, shouldn't take too much effort to get them ready for the desired results.


*And yes I understood you were joking with Newbomb :)
 
273 said:
Not like there a terrible choice, it's probably the one application there a decent choice for, If the OP is great at porting and has a bench etc.. A set of 302's might be the ticket. but I'd still go magnum, shouldn't take too much effort to get them ready for the desired results.


*And yes I understood you were joking with Newbomb :)
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He pokes the bear for fun and sport. I like it.
 
273 said:
This an engine masters 273/292 473 hp at 7,900 rpm
It's got fully ported old school EQ heads

"Hemirunner said:
Stock 273 block 8 sleeves and 3.75 bore for 292 cubic inches
Stock crank
5.4 H-beam Ford rods with EDM pin oiling
Diamond custom pistons with crappy 1/16 ring package
Wet sump oil pan and HV pump with oil crossover
Iron magnum style engine quest heads w/roller rockers, jomar girdles and pushrod oiling
Comp solid roller cam and lifters
Lots better parts today to make way more power"


View attachment 1716334567

View attachment 1716334568
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That's IQ52/Jim's build. Ya ain't gonna get much more.
273 said:
Lots better parts today to make way more power"
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fishmens67 said:
That's IQ52/Jim's build. Ya ain't gonna get much more.
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Didn't say you could, wasn't my quote, 473 hp is pretty good, I do think you could get the torque numbers up though, 328 lbs-ft is only 1.12 lbs-ft that's pretty low.
 
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273 said:
Didn't say you could, wasn't my quote, 473 hp is pretty good, do think you could get the torque numbers up though, 328 lbs-ft is only 1.12 lbs-ft that's pretty low.
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Less torque than a stock 340 or 360 magnum. People see that peak number and get all impressed, not realizing that thing would be a turd in a street car with highway gears
 
I mean I guess if it's all you have, I'd play around with it if I could get parts etc. But what is it finished 200 Horse? that's stock very mid 80s Fox Mustang power. Fun yes but...
 
What makes you think all he can get is 200 hp?

The question is depends how/if the OP goes about it idle-3000 rpm (streetability) could be pretty compromised and is that ok with him or not? If that ain't a huge concern then it's a moot point, next also depends how he goes about it, it can cost more especially piston wise if that's also ok with him then it's really no big deal to build one. If it is an issue then it might/probably be a problem depend how he goes about it.
 
273 said:
What makes you think all he can get is 200 hp?

The question is depends how/if the OP goes about it idle-3000 rpm (streetability) could be pretty compromised and is that ok with him or not? If that ain't a huge concern then it's a moot point, next also depends how he goes about it, it can cost more especially piston wise if that's also ok with him then it's really no big deal to build one. If it is an issue then it might/probably be a problem depend how he goes about it.
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280 is not hard at all @JDMopar got like 280 out of his, and it was somewhat mild really
 
It's (HP) all about air flow (Displacement over Time) = CFM.

At 0.5 lb/h of fuel per hp x 400 hp = 200 lb/h x 12.5:1 air fuel ratio = 2500 lb/h of air divide by 60 minutes = 41.7 lb/m divide by 0.075 lb per cubic foot = 556 cfm.

556 cfm x 3456 = 1,921,536 / cid = rpm

Ballpark 400 hp at same VE% these engines sizes at those RPM will/should be able to displace the same amount of fuel and air (HP).

273 @ 7039 rpm

318 @ 6043 rpm

340 @ 5652 rpm

360 @ 5338 rpm

408 @ 4710 rpm

Obviously with different amounts of lb of fuel per hp and VE% etc.. will change rpm.
 
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