Clevite says,
H Series - •Best to start with when unsure which bearing to choose
•Medium level of eccentricity and high crush
•Enlarged chamfers for greater crankshaft fillet clearance
•Made without flash plating for better seating
•Use with crankshafts that have oversized fillets
•Use with engines that run mid-high RPM range
•Contact patterns should ideally cover 2/3 to 3/4 of the bearing surface

Competition Series bearings have an unusual appearance. They are not the normal white/gray color because the flash tin plate process has been eliminated. Flash tin plating makes a bearing look pretty, but this tin may migrate across the steel back under running conditions and cause undesirable high spots on the I.D. of the bearing. These high spots can intrude into the oil clearance and become concentrated load areas susceptible to premature fatigue. The tin may also migrate into the lining material, reducing it's strength. As an added benefit, the elimination of the flash tin plate allows greater dimensional accuracy. If your engine will be used in competition, or for high performance street use, we highly recommend that you select the Competition Series Rod Sets and Main Sets Super Duty Alloy (CH) Our unique high performance H-14 Super Duty Trimetal Copper-Lead lining material is bonded to an extra-high strength steel backing for unparalleled bearing durability in high stress racing engines. This material will outperform competitors products by a wide margin in virtually any application from street performance to all out racing. We highly recommend this material for any performance use. (Except for blown race applications, which use our Babbitt bearings)
H-14 -The Super Duty Bearing (when strong is better than pretty!)
The unique H-14 lining material found in our Competition Series bearings was specifically designed for high performance, and has a far greater load capacity than any other material We bond this lining to an extra high strength steel backing, creating the best performance bearing in the industry. These materials are Federal-Mogul exclusives, and are not available from any other source.

That's what the main bearings are.

I have new high performance bearings that look like those.

R.