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#2428310 - 01/03/18 11:55 AM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
Al_Alguire Offline


Registered: 01/20/03
Posts: 16715
Loc: Rockville MD & Las Vegas
Lord knows I hate rpm smile
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#2428313 - 01/03/18 12:04 PM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
fast68plymouth Offline
I Live Here

Registered: 01/20/03
Posts: 10767
Loc: So. Burlington, Vt.
I've thrown away enough cracked stock BB Mopar cranks that came out of bracket cars to have reached the point where I now only use them in pretty basic street or street/strip stuff.

No way would I bother having one offset ground for more stroke when I can get a 4340 piece for under $800.

But that's just me.
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68 Plymouth Satellite, 383, stock 906's, 3550lbs, 11.18 @ 123, 1.51 60'
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#2428355 - 01/03/18 01:07 PM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
Transman Offline
super stock

Registered: 03/27/11
Posts: 734
Loc: Michigan
Interesting - you mention big block cranks cracking - how do the Chevy cranks do, do they crack too or not? Ford?

Just you're observation please.


Edited by Transman (01/03/18 03:04 PM)

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#2428384 - 01/03/18 02:36 PM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
EV2Bird Online   penguin-006
No more politics

Registered: 06/23/14
Posts: 3740
Loc: Kansas Roads Between 0 and 140...
May 1980 Hot Rod Mag Al K built a 9:1 505 bracket motor offset a 440 crank to 4.00, six pack rods, iron heads, 332 DC mushroom cam. Mid 10-s in a cuda. Crank work was $300 then.


I can scan it if anyone wants to read it/pics ect.

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#2428401 - 01/03/18 03:05 PM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
Transman Offline
super stock

Registered: 03/27/11
Posts: 734
Loc: Michigan
Yes - scan and post please.

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#2428530 - 01/03/18 07:17 PM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
EV2Bird Online   penguin-006
No more politics

Registered: 06/23/14
Posts: 3740
Loc: Kansas Roads Between 0 and 140...
If you save them you can zoom them a bit and read them.


Attachments
1.JPG

2.JPG

3.JPG

4.JPG



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#2428531 - 01/03/18 07:18 PM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
EV2Bird Online   penguin-006
No more politics

Registered: 06/23/14
Posts: 3740
Loc: Kansas Roads Between 0 and 140...
The Rest


Attachments
5.JPG

6.JPG

7.JPG

8.JPG



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#2428635 - 01/03/18 09:49 PM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
Transman Offline
super stock

Registered: 03/27/11
Posts: 734
Loc: Michigan
Thanks- I remember the article now that I see it. Corky was one of the premier porters back in the 70's and early 80's, Elkins at Diamond was at the top of the heap.

Note the 1.81" exhaust valve, we used those back in the mid 70's - cutting the maxwedge 1.88" down. I sold of bunch of those Stage IV heads back in the day that Corky did for me. Wish I had saved a few sets.

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#2428725 - 01/04/18 01:10 AM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
EV2Bird Online   penguin-006
No more politics

Registered: 06/23/14
Posts: 3740
Loc: Kansas Roads Between 0 and 140...
Its probably been 15 years since I looked at that mag but even then decent mopar builds were not super common then and ive welded and cut alot of cranks over the years for myself, there ugly when balanced but so is my sister and she had two kids. So...

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#2428766 - 01/04/18 07:31 AM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
Transman Offline
super stock

Registered: 03/27/11
Posts: 734
Loc: Michigan
I wonder how many guys put their favorite racing jacket on when they torque their bolts ?

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#2428836 - 01/04/18 10:00 AM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
polyspheric Offline
master

Registered: 10/10/07
Posts: 2608
Loc: New York
Can't follow the text, they refer to "adding 1/2" to the stroke", using the stock rods (no offset), and 505" with 4.00" is just under 4.500" bore - not something you would do.
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#2428854 - 01/04/18 10:20 AM Re: Offset grind 3.75 crank limit [Re: polyspheric]
GTS340 Offline
enthusiast

Registered: 12/06/13
Posts: 320
Loc: Romulus, MI
Originally Posted By polyspheric
Can't follow the text, they refer to "adding 1/2" to the stroke", using the stock rods (no offset), and 505" with 4.00" is just under 4.500" bore - not something you would do.


They welded the journals to get to 4.250 stroke with the stock rods

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#2428975 - 01/04/18 02:10 PM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
Al_Alguire Offline


Registered: 01/20/03
Posts: 16715
Loc: Rockville MD & Las Vegas
My first stroker BB used a welded crank and a Ford piston...Had to get creative in the dark ages smile
_________________________

"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"

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#2430211 - 01/06/18 07:24 PM Re: Offset grind 3.75 crank limit [Re: Al_Alguire]
PorkyPig Offline
mopar

Registered: 08/31/06
Posts: 567
Loc: home in bed
How much difference would 19 cubic inches really make going from 451 to 470? My 3.75 crank is a new offshore 4340 that measures OK. But if I only go to 3.91 I don't know that it would be worth the money for new rods and pistons with only that much offset grind. As a 451 440 block it can run in the high 10s.

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#2430364 - 01/07/18 12:48 AM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 30807
Loc: Bend,OR USA
If your motor makes 1.2 HP per C.I. how much HP does it gain 451x1.2=541.2 HP compared to 1.2x470=564HP.
Of course if it makes more or less HP per C.I. the results will vary accordingly shruggy
I'm not sure about how much the torque gain and PEAK RPM for both torque and RPM are affected by stroke changes confused work
I do know that on my last pump gas street and strip car increasing the stroke .050 (went from 4.25 to 4.300)helped it by .2 ET and 2.5 MPH shruggy


Edited by Cab_Burge (01/07/18 01:10 PM)
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Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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#2430377 - 01/07/18 01:25 AM Re: Offset grind 3.75 crank limit [Re: PorkyPig]
Sport440 Offline
master

Registered: 01/20/03
Posts: 6555
Loc: Canton, Ohio
Originally Posted By PorkyPig
How much difference would 19 cubic inches really make going from 451 to 470? My 3.75 crank is a new offshore 4340 that measures OK. But if I only go to 3.91 I don't know that it would be worth the money for new rods and pistons with only that much offset grind.



If you have all the parts for the 451, rods pistons, etc stay with that.

The 451 is a great motor combo.

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