i have an 88 camaro its tbi but i am going to carb i was wondering what is the biggest cam i can run with the stock valve springs i am looking for a good gain in power and torque with a little thump if i do have to change the springs how hard is it to do with the heads on thanks

 

Its not all about how big. You definitley should have the valve springs, etc checked before just throwing a cam at any engine. If the valve springs won't handle the designated RPM of the new cam it will 'float' and you'll never get the potential of the cam. My suggestion would be to purchase a cam 'kit' from one of the mfgrs. Call them and talk to the tech guy and let him know your expectations. The cam 'kits' usually come with lifters, and springs designed to handle the cam you pick. Of course you'll have to pull the heads off, and get them to a reputable machine shop for cleaning and a valve job. Make sure you request that the new spring are set up per cam mfgr. specs. Installed height, open as well as closed seat pressures. Some shops will simply throw the new springs on. I won't even get into dialing in the new cam during installation. That info is found on any of the cam mfgrs. websites. Its not essential to do so, but your giving away free horse power if you don't.
Good Luck and I hope it all works out ! Remember BIGGER isn't always better, and in most cases it's just wrong.

 

I forgot to mention. Changing valve springs while the heads are still on isn't that hard "IF" its just a simple replacement situation, and you know for sure your valve train parts are 100% within specs. BUT when you get into setting up the heights, open as well as closed seat pressures. Thats a completely different ball game. I don't think it can be done with the heads still installed. Just a hint, to be able to change valve springs with the heads still on, you have to fill the cylinder with air threw the spark plug hole. The air is what holds the valve inits seat. If you have a leaking valve/seat or valve guide the air will leak out and then your valve drops into the cylinder if you have the keepers off. If the air leaks out for any reason at all threw the valve train you need to take them off and get them to a machine shop. Its just that simple. Even a minote pce. of carbon could ruin your day and you would have to pull the heads anyway.
Just not a smart thing to do. Especially if the engine as any big miles on it anyway.

 

There's no use going over 0.450" lift if you're running unmodified swirlport heads. The stock springs will handle that.