There's a loud knocking noise coming from the bottom end, I think it's a rod but I'm not completely sure (I don't know much about motors). My car is driveable, but there's serious power loss and I don't want to mess up the block, so I have it parked right now while I drive the El Camino.

I was thinking about getting the cylinders bored but I'm not sure exactly how much. Max overbore for the 305 is .060" but can that stand up to daily driving (I run my TA as hard as it will go)?

I know a 350 will give me more bang for my buck but I'm sticking with the 305 for now. Since the motor is going to be torn into to repair the problem, I might as well get a little more power out of it in the process.

I know I'll have to get bigger pistons, but what other parts will I need to replace? And how much can I expect to pay to have this done? I was thinking it would be $800 or more.

 

Well for starters i wouldnt buy anything untill you tear the block down. I mean who knows you may get it apart and find the block cracked or that it has already been punched out 60 over and cannot be rebuilt again. Although punched out 60 will be fine and as reliable as a std bore. Ide also not recomend not moreing the cylinders more than you have to. Then you need too look at the economics i mean if it costs 2 grand to rebuild and repair your block or you can buy a new GM short block for $1500 it wouldnt make sence to do it any other way. So for starters i cant tell you how much it will cost to rebuild because that depends on the extent of the damage. Further more i cant tell you what youll need again because it depends on whats damaged. Although i can say dont buy anything untill you know what it will cost. You may find its cheaper to swap to a different motor than repair yours.