77 t-bird

I have a 77 bird with about 65k miles on a reman enginge. I'm having idle problems with my carb. This is the third carb thats been put on there. It is a motorcraft rebuild by holley. Also, i have a vacuum leak that no one can seem to find. I want to change out the manifold and put a holley carb on there and later on rebuild the block with performance parts to get a little more power. Any suggestions

What engine is in it? What kind of performance do you want to get out of it?

I'm sorry, it has a 351 windsor in it. I'm not looking to race it but I want it to put out anywhere between 250 to 300 horses.

Idle problems can be caused by the vacuum leak. Use wire ties as hose clamps and clamp all the vacuum hoses. Spray carb cleaner around the throttle shafts on the carb while the motor is running and see if there is a change in idle. Spray carb cleaner around the manifolds and other areas to try to determine where the leak is.

I agree with Kim. That is probably the first thing to try and tackle that can solve your idle problem. As for mods....well the 351 is a good starting platform. I would have to say a COMPLETE exhaust (I dont think you will even notice a thing with just a cat-back), possibly a larger carb (I dont know what size you are running right now), a more aggresive cam shaft, multiple spark ignition, the list goes on and on. I would start with the exhaust though and then move on to the cam and carb at the same time (make sure to size the carb with according to the cam's intake lift and duration if you decide to go with that option).