hey guys when i apply my brakes at idle the rpms rise about 200 .and also when coasting down to a stop the engine acts like it wants to die .they are power brakes on my 68 .thanks jeff

Sounds like a vacuum problem.

When you disconnect a vacuum hose, does the RPMs rise also (a small hose, not the power brake hose)?

Ditto -- I suspect the power brake booster is where the problem is.

Do you have some sort of after market a/c? The device for reading extra power usage to kick the idle up might be reading your brake lights going on and kicking the idle up. Then your idle might be set too low. And also your battery might be going bad. Make sure your battery connections are good allowing the transfers. Try hitting the horn or watching the lights when it's doing the chugging acting like it wants to stall. Well there's the extra possibilitys.

no it has no a/c and has a new battery fresh tune up would the float level in the carb affect this situation

I don't think it would be a float problem - doesn't hurt to check, though.

Did you try removing a vaccuum hose?

Check the booster by pushing brake pedal several times with engine off. Keep your foot on the pedal and start engine. The pedal should go down a little with a good booster.