Is it a bad ideal to put a new cam such as a hot cam into a motor with 100,000 miles on it? This is for a 95 Lt1 with a 2500 stall and 3:42's in the rear.Street car only will never see the track.

 

The installation of a cam. on an otherwise "GOOD" engine will not hurt anything at any miles. The question when becomes is an engine with 100,000m on it a "good" engine.
Any thing that breaks after the install will be blamed on the install.

 

First off get a compression test and leakdown test done.

Then make sure your cam bearings are in good condition. It's a good idea to get those installed with your cam if it has a lot of miles though 100k isn't that bad. I plan on doing it to my car with 195k miles on it... Probably 200k by the time I get around to it. If the engine and bearings are in good condition then go for it. Make sure the cam is installed PROPERLY. Do not let it rest half in and half out because this will take off the grease needed to lubricate it for it's first start up.

Also new valvesprings/rockers/pushrods/basically the entire top end minus the cylinder heads themselves and valves should be replaced.