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02-09-2021, 06:19 PM | #1 |
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Dumb question... +/- .015 on crankshaft
Ok dumb question, how much power is there in having the crank machined +.015 on a sbc. Is it actually worth the expense? Is there another purpose for this other than added stroke?
Thanks, John Beasaw |
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02-09-2021, 06:28 PM | #2 |
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Re: Dumb question... +/- .015 on crankshaft
Yes.
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02-09-2021, 06:37 PM | #3 |
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Re: Dumb question... +/- .015 on crankshaft
If you are making 1.5 HP per cubic inch, in theory you add 1.5 HP for every cubic inch you add.
A correctly stroked crankshaft will also correct a poorly indexed crankshaft.
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Dean Feiock -- Stock 5002 |
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02-09-2021, 07:24 PM | #4 |
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Re: Dumb question... +/- .015 on crankshaft
I personally have found cubic inch to be worth nothing with induction, comp, and cam being the same in a modest bracket race situation.
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02-09-2021, 09:01 PM | #5 |
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Re: Dumb question... +/- .015 on crankshaft
It depends, if you want to run with the BIG DOGS, ...you can’t leave ANYTHING on the table.....
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02-09-2021, 09:34 PM | #6 |
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Re: Dumb question... +/- .015 on crankshaft
It's the thing you do when you want that "LAST" little bit......
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02-09-2021, 11:06 PM | #7 |
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Re: Dumb question... +/- .015 on crankshaft
On a Stock or SS we always run .013 stroked crank.
Has to be indexed anyway at least with all our Mopars I have seen 10 stockers in class within less than a Tenth of a second One year in Class in Denver Natl's = we had a race decided by .0001 Plenty of Class racing with an hundred or two!
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John Irving 741 Stock 741 Super Stock |
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02-10-2021, 04:25 PM | #8 |
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Re: Dumb question... +/- .015 on crankshaft
Dean is correct, you're effectively killing two birds with a single stone!
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Jim Kaekel 3836 STK |
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02-10-2021, 08:18 PM | #9 |
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Re: Dumb question... +/- .015 on crankshaft
Adjusting stroke will not correct index. To fix index try to find a grinder, machine, with new or rebuilt chucks that has index stops at 90*. After its index always check TDC and zero on damper. Rolling the crank to get it to "clean up" @ .020" under while stroking it .014" will some time change the relationship between the two. To check quick index #1 and #6 should arrive at TDC at the same time using two dial indicators.
We use to grind cranks for Kuntz & Craft years ago. In fact we have lost to a 428 heads up with a crank we stoked and indexed for Jim and Keith. |
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02-10-2021, 08:51 PM | #10 |
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Re: Dumb question... +/- .015 on crankshaft
Thanks for the insight. I knew the rules allowed indexing/stroking, i just wasn't sure if there was a large enough advantage vs expense.
As for my combination i don't have a budget to run with the big dogs. Game plan is .40-.50 under in the heat just to play. Thanks John Beasaw |
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