Stock banjo bolt oil port diameter

[zeeboost]

I'm almost finished converting my brother's '77 n/a to a turbo, but I need some info for the banjo bolt that feeds oil to the turbo. I don't have the factory banjo bolt but I've already drilled out a bolt with a .063" bit, however the more I think about it, the more I don't want to restrict the oil to the turbo. I'm afraid that the oil will coke and clog that small passage much easier in the restricted banjo bolt than whatever size the factory orifice was, here's why:

 

- It's not a water-cooled turbo...just a rebuilt factory t3

- He's not running an oil cooler

- Although I'll tell him to let it idle for a couple minutes before he shuts it off, I doubt he'll do it every time

- With him being a poor college kid, I doubt he'll use the best oil on the market

- With the factory setup, I haven't seen any issues with too much oil pressure blowing out the seals

 

So, I think I'm going to drill my bolt to be a little larger and I'd like to just stick with the stock size that the factory used...I just need to know what size that was