Normally I would advise people to just go with the chevy, but you sound like you have an idea of whats going on so you can handle the olds.
A set of resricted push rods is in order. The oiling mods you are planning sound good. The olds likes to send all the oil up top and then starve the crank. Need to make sure the oil has a way to get back to the pan, and quick. Make sure you drill the heads for the oil drainback into the pan. I'd ditch the modified pan and buy something quality that will give you some oil control.(try armando's, the price is comparable with a dooley I believe and is far superior). If you do go with a new pan, make sure it has the bungs for oil drain, temp sensor & the drains from the heads.
The olds can be made to live. Good machine work and researching how to make them run and you will have a good performer. An oil cooler would be a wise investment too. The biggest pan you can find would help also.