Oil Mods 440

There is lots of info on this , almost to much , confusing .
A fresh look
I drive my Dart w a 440 at Road America and other tracks for fun, track days . I also drive it to work and pretty much all over
I have trouble with the main bearings failing.
446 CI RPM is 3500 to 6000 for 20 minutes at a session
10.5 to 1
Crane Roller rockers 1.6
Source one AL heads
M1 intake
EFI Carb
Milodon Pump HV
8 quart road race pan w swivel pickup and baffles
3 quart engine accumulator
Purplestick 557 lift dur 296 108 centerline
Manual Trans
> Should I use full grooved bearings or 3/4 ?
> too bush mech lifters or not to ?
> I have read about opening up some of the oil passages with a reamer ?

Any suggestions besides use a smallblock or an after market block are appreciated

Thank You,
Bill