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

Re: Dumb question... +/- .015 on crankshaft
 

Yes.

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.

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.

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.....

Re: Dumb question... +/- .015 on crankshaft
 

It's the thing you do when you want that "LAST" little bit......

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!

Re: Dumb question... +/- .015 on crankshaft
 

Dean is correct, you're effectively killing two birds with a single stone!

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.

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