Thanks for all the good info. I just did the oil mods to the main oil galleries as described by guitarjones, but I'm not going to tube the lifter bores. I guess just reaming out the mains to 1/2" will be sufficient enough with an HV oil pump.
Reaming out the mains to 1/2"? I sincerely hope your not talking about drilling the main bearing feeds to 1/2". That'd weaken the block considerably and wouldn't gain anything because the feed holes in the main bearings aren't very big. I drill the main feeds to 9/32". If your using a HV pump make sure and use a good aftermarket pickup because the stock pickup is too restrictive and you don't gain anything.