okay i have a 91' ls and im about to redo the vaulves but my friend suggusted that i should take it to his mechanic and have them bore it .60mm over and drop in some new weisco pistions and do a whole new head and i got to thinking its not a bad idea im getting horsepower increase and the enging is going to be underwarranty and also it saves me time from having to do it. so i just wanted to know if any one knows what a job like this would cost and if someone could tell me some performance numbers i might expect to see in HP.
hachacker5024 is offline Reply With Quote

 

Your not going to gain any performance from the bore, the only performance increase you'll se will be from the pistons. The amount depends on the compression ratio you go with.
Rods and pistons will run you about $900 (wiseco and eagle).
Head work I'm not sure on price, but depending on what you have done, anywhere from a few hundred to a few grand depending on how far you go.
If you just do cams, springs and retainers, you'll see some bump, but if you do valves and P&P, port matching, etc you'll see more gains....remember to get the most out of the set-up you'll need to tune it.