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hello I have 99 trans am ls1. approx 130,000 miles. I recently did a head and cam swap on my stock ls1. I have not started the engine with the new swap. upon assessment I noticed I have a small hole approx 1/4inch on the front passenger side of the block. I can see thru to the other side. I have barely driven the car in the past yr so I noticed no fluid loss or stains on the ground but I wasnt looking for any it operated normal. my main concern is the block. is it ruined?
does this happen to aluminum blocks? I have never recalled for them to do this.i got s screw driver and pushed around the hole to see if it would get bigger but nothing happened. any help is greatly appreciated.
From your pictures it’s really hard to see exactly what part of the block this hole is. It looks to just be through the webbing. If it’s not through the crank case, I’d say it’s no issue.
OP, it's there from the factory. From what I can tell, the early LS1s had them at an angle near the block web and some of the later LS engines had them a little farther forward in just the flat area.
Last edited by 93Z2871805; Jul 5, 2021 at 09:40 AM.
appreciate it 93z28 I had no idea they had holes. I was looking on google and some books but could never find a decent picture. well I feel better. i really appreciate all the feedback and help from everyone. thank you
That hole is normal on the ls1 blocks. Mine has same hole on passenger side and I've seen a few others with the same hole. You can clean it well and jb weld both sides if you want, but it's not needed.
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small hole in front of block 
