My '95 NA had a leak at the Tree after a rebuild/Bore. Same Block, Same Bolts, but the Bolts were hitting the Bottom of the Tree Block threaded Holes. I had to Cut a few threads off the Bolts to get it to seal.. Might want to check that. I week after I had to do it to mine, another poster here had the Same Problem.. he also had to cut his bolts..
At 150 Miles I'd already changed my Oil Three times.. have you changed yours yet?.. also cut your oil filter and look at the debris.. I found ONE little TINY Curl from a Bearing, babbit on one side and copper on the other.. other than that just the GOBBS of metal shavings from the Cylinder Walls.. give the oil that 'Shimmer' look.. have 1K miles on it now and 5 oil and filter changes.. all looks good.. the 'Shimmer' stopped at about 250 or so miles.. waiting for 3K to push it hard..