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Small block 408 stroker

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Over 10 years with the same crank,,,full groove bearings.

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Ixnay on the full groove !!

From Clevite ...

First, it’s essential to understand that bearings
depend on a film of oil to keep them separated
from the shaft surface. This oil film is developed
by shaft rotation. As the shaft rotates it pulls oil
into the loaded area of the bearing and rides up
on this film much like a tire hydroplaning on wet
pavement. Grooving in a bearing acts like tread
in a tire to break up the oil film. While you want
your tires to grip the road, you don’t want your
bearings to grip the shaft.
The primary reason for having any grooving in a
main bearing is to provide oil to the connecting
rods. Without rod bearings to feed, a simple
oil hole would be sufficient to lubricate a main
bearing. Many early engines used full grooved
bearings and some even used multiple grooves.
As engine and bearing technology developed,
bearing grooving was removed from modern
lower main bearings. The result is in a thicker
film of oil for the shaft to ride on. This provides a
greater safety margin and improved bearing life.
Upper main shells, which see lower loads than
the lowers, have retained a groove to supply the
connecting rods with oil.
In an effort to develop the best possible main
bearing designs for performance engines, we’ve
investigated the effects of main bearing grooving
on bearing performance. The graphs on the next
page illustrate that a simple 180° groove in the
upper main shell is still the best overall design.
While a slightly shorter groove of 140° provides a
marginal gain, most of the benefit is to the upper
shell, which doesn’t need improvement. On the
other hand, extending the groove into the lower
half, even as little as 20° at each parting line
(220° in total), takes away from upper bearing
performance without providing any benefit to
the lower half. It’s also interesting to note that as
groove length increases so do Horsepower Loss
and Peak Oil Film Pressure which is transmitted
directly to the bearing.

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I use the Clevite full groove bearings....???

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Is it also good to use -.001 bearings for better clearance also? This is what a friend always uses.

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Maybe if your on the tighter side but if you set the
crank for the the looser side you wont need those...
I set everything at .003... and I've been running a
1/2 groove for a long time... just like that article
said... I want the larger load carrying area