What is the most horsepower than an LT1 block has taken and how long did it last? I have a very stout little short block but now I am thinking of changing up a few things and going a differerent route "cought91cough" and just wondering what these blocks will take. It's half block filled and 4 bolt main. Eagle 4340 Crank, Oliver I beams, Diamond Pistons but I'd probably have to get billet rods/pistons and I don't know about the crank.

 

Lots of turbo cars pushing 1200+hp with no major issues.

 

I've seen a factory 4-bolt LT1 block make 1,125flywheel HP, running about 20# of boost. Since it was an S/C, the power at the crank was probably over 1,250HP. There was no block fill used. After pushing a 3,900# 30th SS convertible to 9.03 @ 155MPH, the block was sold to another person, who is using for a high HP nitrous motor. It was in excellent condition. But the 30th SS was going for 1,325flywheelHP, and they didn't think the stock block would take it, so they switched to a Dart Iron Eagle. Car has now run 8.6@160MPH with that engine.

I also believe Madman claimed 1,200HP on his ATI S/C'd LT1, another car running 9.11@155MPH.