I have a 96 Lt1 m6 camaro. Ive done the basic bolt ons, exhaust, headers, intake, maf. Lately it seems like it just keeps getting slower. Any ideas on things to replace on a high mileage engine like mine? its got like 180k on it, so its seen better days. I do regular maintenance like oil, fuel filter, spark plugs, wires, etc.

 

It may seem like it's tired because you may just be used to the power. Only way to really know it a dyno but with 180k on the clock you may be right. Only real way is to drop in a fresh block. Plan on doing a rebuild. If the car is running fine and not buring oil then that gives you plenty of time to search for the best prices.

 

could be catalytic converter is getting pluged. did u change it/them when u did the exhaust?

 

Does it still have a Cat on it. Most comon complaint about a semi plugs cat converter is lose of power.
High mile motors can drop compression but generally the blow by gets real bad. With the roller cams wear is not normally a factor. A streched timing chain can drop power some so yes your motor will drop power as it ages but unless you are talking .1 or .2 in the quater mile ther is something wrong.

Normally is a motor is starting to reach its limits you will see a drop in oil pressure and bad oil leaks from the blow by and it will smoke either from the oiling ring being worn or the PVC system not being able to handle all the blow by.

 

How much money are you willing to spend, and what sort of mechanical skills do you have?

If you can, I'd suggest just a bottom end refresh. Pull the engine, disassemble, .030 over at a machine shop, throw in some new pistons/rings and all new seals, and voila! You've got a like new 355!

 

if you have strong compression in the engine, not losing any fuel mileage, not burning oil or leaking any, and you've been mantaining it, then there is nothing wrong mechanically. the LT1 is full of wires...age and heat eventually takes its toll on them.

i would assume you're just used to the power. GM made that engine to last like any other.

 

i used to have this old 85 shortbed, and it had the original pipes and cat on it, and we cut it out and just ran a straight pipe through it, and before that it had slow accel and it had 135K hard miles, and after cutting it out it ran allot better so you might have to just cut out the cat

 

Replace the O2 sensors. Take out the injectors and have a reputable shop clean and replace seals. Seafoam it.