Questions about my '73 Charger SE 400/auto Engine Problems etc

[98neongirl]

I am not too familiar with rebuilding older car engines, so I am looking for some helpful tips and advice....
There is a vacuum leak with my '73 Charger SE, 400ci, auto trans. It will start, but it won't stay running if I don't give it some gas. How do I diagnose it and how do I fix it? I have been told to get a new carburetor or carb riser plate but will that fix it? If it is a leak then shouldn't a line be replaced or tightened somewhere? Sorry if these sound stupid but LOL I have a lot to learn about my cars' engine. Like what to do, what not to do, which parts offer better hp gains, etc.

My goal is to get it running right first, and eventually do a few things to add some power to the engine. I asked this question in another thread of mine but I have a few other things to ask, so here goes:

I believe the stock horsepower is 175 or 185, which doesn't sound like much for such a heavy car. I am on a tight budget, but I want to add some HP so it, just enough to hold my own. I am thinking 300hp sounds decent, I don't want to do a motor swap or complete rebuild (I plan on rebuilding it, just not for a while)...so what are some parts I could buy at decent prices to up the horsepower little by little? This is a winter project but come spring I am hoping to drive it somewhat often, but not exactly as a daily driver, just on nicer days. It supposedly has 25000 original miles, if I mod it a little will that depreciate it's value a considerable amount?

It needs new quarters, a drivers side fender, pass. side lower fender patch panel, and maybe a new trunk lid. I also need to get new headlights for it, but I don't want to get NOS pieces, I have seen some diamond clear round headlight conversions that allow an H4/9003 bulb to be used. I would really like to do that, for better vision at night... how would I go about converting the current headlights to the H4 bulb/light housing? Also, how do I measure the diameter to know which size headlight to order? There are a few 5 and some odd inch ones....

Well, thanks for any help, I really appreciate it!

[myk]

Vacuum leaks can be from various lines on your engine, so try to visually inspect them for wear and damage and replace if necessary; I'm not sure what the differences are between a '73 and earlier motor so consult with a shop manual or other visual resource-more than likely someone else will chime in here.  'Carb to intake manifold or intake manifold to head vacuum leaks can be spotted by spraying something like 'carb cleaner around the mating surfaces of these engine parts, and then seeing if the idle speed changes...

[RD]

make sure all vacuum ports on your carb are blocked off.  make sure your vacuum tree on the backside of your intake has all hoses hooked up to it.  make sure your brake booster hose has no cracks in it.  get soapy water and spray at the base of your carb while its running to see if the base gasket is bad.  you can spray soapy water around your intake also.

[Chryco Psycho]

it may not have a vacuum leak at all it is more likely to be simple tunign adjsutments , when cold it will need more fuel to keep running so the choke may not be operating , advancing the uiintial timing may help as well