Quite frankly the Buick oiling system sucks! Because of it you need to run very tight bearing clearances. Also need to pay very close attention assembling the oil pump it needs to be blue printed too. Front cover can be reworked as well as other oil passages to improve the overall oiling system. Little things like knowing to throw away the timing chain tensioner if you go to a roller chain. knowing to replace the camshaft button with a roller bearing type button. Not to mention its a v6 performance engine. There are not as many main caps everything is smaller and lighter so it needs to be put together right as is not a lot of room for error.......
Please do not take my comments personally but you are off-base with your statements about the oiling system sucks as well as clearances?
You are correct as there is "not a lot of room for error", and this is true for any engine build.
No matter if it is a Chevy, Ford or any make, expertise and knowledge is gained by actual experience which includes feedback from field testing and use. There is NO substitute for this.
My records show we have built over 700 Buick turbo V-6 engines from stock to 7 sec. GN's and have learned the hard way what NOT to do as well as the BEST methods and procedures to have the engine perform as ordered, and still be reliable.
We have no "secret" formula, but what methods and procedures we have learned over the years gives us an edge on those still learning.
I am not saying we are the "best", but we have worked with other competent engine builders around the country, and shared information with them as well. We have "fixed" and rebuilt many engine shipped to us after the customer got fed up with his local builder costing them lots of grief and $$$$ for their expensive build.
Just like the GN transmission, only a few builders around the country really have knowledge and experience to build one that will do the job and be reliable for lots of use, so why would someone just pick an unknown engine builder instead of an experienced with GN engines?
At least check with GN customers, not just take the shop's word, that have actually had work done by a shop to verify how well it turned out before you spend your $$$$ there.