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#1080883 - 09/23/11 12:48 PM New idea for a 273 stroker
dogdays Offline
I Live Here

Registered: 01/20/03
Posts: 13758
Funny how my mind works...

The NASCAR boys are using a lot of 0.866" pins to save weight. Consequently there are a lot of 1-race rods floating around with that weird pine size.

Today I was studying my KB catalog and came across the piston for a Toyota 22R. Bore is 3.622, available in oversizes. The piston weighs less than 400 grams and has a 0.866 pin. Compression height is something like 1.35"

Anyway I did the math and came up with an ideal rod length of 6.225". That's close enough to 6.200".

So it all fits in a 273 block and should rev easily, as long as you can find 6.200 rods with a 2.0 or similar crankpin size and pin of 0.866.

Anyone want to try? It's a 330.

R.

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#1080884 - 09/23/11 02:43 PM Re: New idea for a 273 stroker [Re: dogdays]
scratchnfotraction Offline
I Live Here

Registered: 05/29/03
Posts: 14601
Loc: Florida


very interesting indeed.

only 19 cubic inches behind a 360 crank in the 318 block for a 349 stroker.


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#1080885 - 09/23/11 04:19 PM Re: New idea for a 273 stroker [Re: dogdays]
dart4forte Offline
I Live Here

Registered: 01/31/03
Posts: 10947
Loc: Mesa, Arizona
I have a recipt for a destroked 273, 258CI

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#1080886 - 09/23/11 04:25 PM Re: New idea for a 273 stroker [Re: dart4forte]
convx4 Offline
mopar

Registered: 02/09/05
Posts: 552
Loc: STL
I got to ride in a de-stroked 318. It used the 273 crank. 305 CI like the Real Trans Am racers. I have an old mopar engine book with the build specifics. This motor was in a 69 dart. It would rev way up fast and blast off the line. This would help keep it in the winning position. I ways wanted to build one.


Edited by convx4 (09/23/11 04:25 PM)

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#1080887 - 09/23/11 04:40 PM Re: New idea for a 273 stroker [Re: dogdays]
Fat_Mike Offline
mopar

Registered: 05/08/03
Posts: 522
Loc: N.W. Florida
Very interesting indeed. Would these work?

http://www.roushyatesparts.com/parts-p/rye-b110007u.htm

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#1080888 - 09/23/11 04:48 PM Re: New idea for a 273 stroker [Re: convx4]
Locomotion Offline
master

Registered: 01/19/03
Posts: 5202
Loc: Florida
Quote:

I got to ride in a de-stroked 318. It used the 273 crank. 305 CI like the Real Trans Am racers. I have an old mopar engine book with the build specifics. This motor was in a 69 dart. It would rev way up fast and blast off the line. This would help keep it in the winning position. I ways wanted to build one.




273 cranks had the same 3.31" stroke and journal diameters as 318's and 340's. The Trans Am cranks had something like a 2.96" stroke.

One problem with a stroked 273 is that despite the extra cubic inches, the bore size would limit valve size and breathing. I would think that it would make a lot more torque.

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#1080889 - 09/23/11 07:51 PM Re: New idea for a 273 stroker [Re: Locomotion]
scratchnfotraction Offline
I Live Here

Registered: 05/29/03
Posts: 14601
Loc: Florida
Quote:

Quote:

I got to ride in a de-stroked 318. It used the 273 crank. 305 CI like the Real Trans Am racers. I have an old mopar engine book with the build specifics. This motor was in a 69 dart. It would rev way up fast and blast off the line. This would help keep it in the winning position. I ways wanted to build one.




273 cranks had the same 3.31" stroke and journal diameters as 318's and 340's. The Trans Am cranks had something like a 2.96" stroke.

One problem with a stroked 273 is that despite the extra cubic inches, the bore size would limit valve size and breathing. I would think that it would make a lot more torque.




torque rules for for fun factor

the whole point of a stroker..no?

I know my uncle had a stock hipo 273 with a .500 lift solid cam that was a beast for a 273 with 4-speed and 3.91sg and it would buzz real high rpms.

I am thinking a 330 or 349 would be real cool on the street as a daily driver and the 349 would not need the bore notching and could use 360 heads


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#1080890 - 09/24/11 04:39 PM Re: New idea for a 273 stroker [Re: Locomotion]
jcc Offline
I Live Here

Registered: 12/21/03
Posts: 14068
Loc: Ethereal
Quote:

One problem with a stroked 273 is that despite the extra cubic inches, the bore size would limit valve size and breathing. I would think that it would make a lot more torque.




Relative to what, a 273, duh, a stroked 318, no, a stroked 340, no, a stroked 360, no. Stroking just makes more or less more torque realtive to hp, not just goobs of torque.
_________________________
“Strong minds discuss ideas, average minds discuss events, weak minds discuss people.”
― Socrates

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#1080891 - 09/24/11 05:04 PM Re: New idea for a 273 stroker [Re: jcc]
Fat_Mike Offline
mopar

Registered: 05/08/03
Posts: 522
Loc: N.W. Florida
Quote:

Quote:

One problem with a stroked 273 is that despite the extra cubic inches, the bore size would limit valve size and breathing. I would think that it would make a lot more torque.




Relative to what, a 273, duh, a stroked 318, no, a stroked 340, no, a stroked 360, no. Stroking just makes more or less more torque realtive to hp, not just goobs of torque.




What I read into this recipe was a 273 with a few more cubes, and a light rotating assembly. So in a nut shell, it isn't necessarily building up a powerhouse 273, but building a well balanced 273 with a light rotating assembly that will spin up to 7.5, maybe even 8K RPM's. Therefore upping the HP, not just torque. Something that would work out great in an early A-Body. Aside from the "knowns" of what other motor combo's have proven, it would be interesting (IMO) to see the numbers this recipe would make.

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#1080892 - 09/24/11 05:31 PM Re: New idea for a 273 stroker [Re: Fat_Mike]
dogdays Offline
I Live Here

Registered: 01/20/03
Posts: 13758
Thanks, that is where I was headed. Basically 273s and 318s are free engines. You can always build a bigger engine for about the same price. But, suppose you want a stronger 273 Dart with the original engine? Or suppose you have a free 273 block and dare to be different? Those rods are NASCAR quality and usually available for a couple of hundred $. The pistons are quite inexpensive and with pin about 200 grams lighter than a 273 piston and pin. 2.50 main stroker cranks are all over the place. Yes, the smaller bore limits head flow, but how much flow do you need with a 330?

Check back next week for the next installment of "dare to be different" stroker free blocks. Hint: What's 24mm got to do with it?

R.

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#1080893 - 09/25/11 02:31 AM Re: New idea for a 273 stroker [Re: dogdays]
jcc Offline
I Live Here

Registered: 12/21/03
Posts: 14068
Loc: Ethereal
Different? Take a 340, bore it .060, destroke it back to a final 273, use superlight pistons, use roller cam, wind it to 9800, drop the clutch and hang on, and blow away all the other 273's.
_________________________
“Strong minds discuss ideas, average minds discuss events, weak minds discuss people.”
― Socrates

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#1080894 - 09/25/11 08:56 PM Re: New idea for a 273 stroker [Re: jcc]
A990 Offline
pro stock

Registered: 01/19/03
Posts: 1434
Loc: Oregon
Quote:

Different? Take a 340, bore it .060, destroke it back to a final 273, use superlight pistons, use roller cam, wind it to 9800, drop the clutch and hang on, and blow away all the other 273's.




Well since 273/318s are still in the JYs and the 340s have long ago disappeared, this is a great idea

I have a 65 block and heads in my garage begging to be put to use again.

One thing for Dogdays-

Wonder how a turbocharger would work?
_________________________
Torque. It does a body good.

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#1080895 - 09/25/11 09:09 PM Re: New idea for a 273 stroker [Re: A990]
69B3GT Offline
Ready For A Change

Registered: 10/04/08
Posts: 1843
Loc: Mira Loma, CA
I still have the 273 out of my dart sitting in the garage

If I get another car id like to do something different
_________________________
Union Mechanic (Local 12) Big block 69 Dart GT. "Fear is momentary, Regret is forever."

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#1080896 - 09/26/11 05:58 AM Re: New idea for a 273 stroker [Re: 69B3GT]
scratchnfotraction Offline
I Live Here

Registered: 05/29/03
Posts: 14601
Loc: Florida
Quote:

I still have the 273 out of my dart sitting in the garage

If I get another car id like to do something different




a little 273 with the hipo solid lifter cam at .500 lift is pretty nasty in a 66 dart with 4 speed and 3,91sg, my uncles would buzz right up around 6500 rpm and whooped up on some 327 chebby back then.

ask the Rev about his "class of 65" with the record holding 273,IIRC it still holding the record today.

now thats a little bad azz 273 right there

it can be done but you "gotta want it"

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#1080897 - 09/26/11 07:35 AM Re: New idea for a 273 stroker [Re: scratchnfotraction]
69B3GT Offline
Ready For A Change

Registered: 10/04/08
Posts: 1843
Loc: Mira Loma, CA
Quote:

Quote:

I still have the 273 out of my dart sitting in the garage

If I get another car id like to do something different




a little 273 with the hipo solid lifter cam at .500 lift is pretty nasty in a 66 dart with 4 speed and 3,91sg, my uncles would buzz right up around 6500 rpm and whooped up on some 327 chebby back then.

ask the Rev about his "class of 65" with the record holding 273,IIRC it still holding the record today.

now thats a little bad azz 273 right there

it can be done but you "gotta want it"




Maybe one day ill get around to building a wild 273...just gotta get this big block car squared away..one of these days
_________________________
Union Mechanic (Local 12) Big block 69 Dart GT. "Fear is momentary, Regret is forever."

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#1080898 - 09/26/11 12:47 PM Re: New idea for a 273 stroker [Re: scratchnfotraction]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
Quote:

Quote:

Quote:

I got to ride in a de-stroked 318. It used the 273 crank. 305 CI like the Real Trans Am racers. I have an old mopar engine book with the build specifics. This motor was in a 69 dart. It would rev way up fast and blast off the line. This would help keep it in the winning position. I ways wanted to build one.




273 cranks had the same 3.31" stroke and journal diameters as 318's and 340's. The Trans Am cranks had something like a 2.96" stroke.

One problem with a stroked 273 is that despite the extra cubic inches, the bore size would limit valve size and breathing. I would think that it would make a lot more torque.




torque rules for for fun factor

the whole point of a stroker..no?

I know my uncle had a stock hipo 273 with a .500 lift solid cam that was a beast for a 273 with 4-speed and 3.91sg and it would buzz real high rpms.

I am thinking a 330 or 349 would be real cool on the street as a daily driver and the 349 would not need the bore notching and could use 360 heads






no, the whole point of a stroker is to add displacement...stroke is just a more convienient way to add displacement. one of the mags like hotrod a number of years ago built up 2 383ish cheby motors with identical components, save one was "all bore" with an aftermarket block and stock 350 stroke, the other was all stroke. compression was the same for both. the results? they made essentially the same power, with the "all bore" motor besting the stroker by a few HP/tq due to less valve shrouding. so your exotic, expensive 330CID 273 based stroker has the same HP/tq potential essentially as a .060 over 318....or less than a stock stroke 360....

the other issue with a 4" arm/6.2" rod (1.55 rod ratio) motor is piston velocity....with a stock replacement type cast piston, I wouldn't recommend going past 4000 ft/sec for a mean piston speed, which limits you to ~6000 RPM.
_________________________
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2006 Inferno Red Dodge Caravan SXT 2011 Toxic Orange Dodge Charger R/T

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#1080899 - 09/26/11 01:18 PM Re: New idea for a 273 stroker [Re: patrick]
Neil Offline
I Live Here

Registered: 01/19/03
Posts: 10987
Loc: Eagle, Idaho
What sort of heads + intake would work good with a 'big' 273? If the engine can turn 7k+ you would need heads that flow at that rpm. Would a set of ported magnum heads work? I assume a 2.02 valve head doesn't fit on a 273 block?

A set of old school iron W2's would be a fun experiment if they fit.

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#1080900 - 09/26/11 01:42 PM Re: New idea for a 273 stroker [Re: Neil]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
anything larger than the stock 1.78/1.5's require notching of the bore for pbysical clearance
_________________________
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2006 Inferno Red Dodge Caravan SXT 2011 Toxic Orange Dodge Charger R/T

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#1080901 - 09/26/11 02:04 PM Re: New idea for a 273 stroker [Re: patrick]
scratchnfotraction Offline
I Live Here

Registered: 05/29/03
Posts: 14601
Loc: Florida
so a ported set of #302 heads with stock size valves will work and be a closed chamber.

as far as bore notching goes on a 273, correct?

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#1080902 - 09/26/11 03:47 PM Re: New idea for a 273 stroker [Re: scratchnfotraction]
dogdays Offline
I Live Here

Registered: 01/20/03
Posts: 13758
The whole idea is to use a free block and cheap components to build a usable street motor. I've suggested Magnum heads in the past but they will require bore notching, which member Bigblockranger did in the car with a Dremel using coffee filters in the block to catch the chips. Hardly high tech!

Or home port a set of 302s.

If building a high rpm motor I would use expensive components and most likely build a much larger engine.

For this build it is max out the cubic inches, keep the rpm manageable and use a relatively cheap valvetrain.

R.

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