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

[HP HUNTER]

As far the BBC crank stroke go they can vary quite a bit, lets take a 454 cast 039 crank for instances, the factory grind had a high of 4.010 and a low of 4.002, we indexed it and ground it to 4.010. We just did a steel 454 7416 that came in at a low of 3.990, it was indexed and ground to 3.990. Just because its suppose to have a 4.00 stroke and be equal on all four pins, its NOT. So it makes since any crank prepped for a stocker would be indexed and ground .013 over factory specifications.

[Larry Hill]

We had a crank in the shop that was .011” long from the factory but the index was off a few degrees. It still made a good stroked stocker crank at .010 .010. Informed the customer we had to roll the crank to get it to index and the timing marks would be off at TDC on the damper.

[Mike Taylor 3601]

I go with the every little bit helps theory.. 1 here 2 there 5 there all ads up into a bigger number....
the+.013 stroke is the probably least amount of gain in the crankshaft mods.. I believe the equalizing of the stroke and the indexing of the throws are the more important...
getting all the cylinders equal on stroke and same timing...having all the cylinders equal, producing same power..you could ride a bicycle with two different length cranks for the pedals and have them 120* apart, but it sure wouldn't be smooth or very efficient
when you are grinding a stocker crank you better have a stroke gauge.. crank grinders are set for stroke but it doesn't always come out exactly what it is set to .... we go +.013 and if you miss by a couple thou on the stroke wont check legal... I check stroke as I go and some times have to adjust +/- a few thou on stroke...
best I can tell around .040' on index=about 1*

[HP HUNTER]

Every crankshaft grind starts with a straiten and then this.