Recently, my car was sputtering and backfiring. I thought it was a clogged coil or injector because I got a missfire code on #7. I know Compression readings should be in the 160 range on a stock LS1. I went ahead and did a compression test. My number 7 was at 30. I was shocked! I still can't believe I was driving my car in that condition. So now my question is: Is it worth fixing my issue or buying a used block? I have a friend who is selling a used motor for $1,300(80,000Miles). I dont want to spend too much money. , Thanx!

 

I would pull the valve cover and look closely at the springs on #7, that would be the cheapest fix anyway. Then maybe buy/borrow a borescope to take a look through the spark plug hole and see what's going on.

 

Ill try that. Thanx

 

Hope your piston doesn't look like my #7

 

Yep check your valvetrain to make sure it's not something up with it.

 

Geez what happened to that piston....

 

unlucky #7, I've been searching the **** to try & understand the consistent failure.

 

^^^I've been seeing this constant problem. I'm buying a used engine for now.

 

Does anyone know what it would cost to fix the issue(if it is the piston)?

 

Depends on the extent of the damage. If the cylinders are barely scratched up its worth rebuilding to a 347 and would cost roughly the same. Plus you would have a stout bottom end.