Howdy Mark,
We need more info... read the last suggestion...
Any engine is just a big air pump. The trick is to get more air in, light it, and then get it out.
A cam will give you more power with no other changes, BUT (don't you just hate big BUTS) it will give you MORE power if you have a bigger carb and headers and DuraSpark II to go along with the cam;s increased power..
First, I'd start by improving the ignition to an electronic DuraSpark II (DSII) distributor. (Read the Sticky on doing that)
Next, I'd then I'd add a bigger carb.
Then I'd improve the exhaust. (large single exhaust - with or without headers)
Now I'd change the cam. BUT, only if the rings and bearings are good.
We need to do one more thing with the air passing through the engine - compress it. You'll have to remove the head to change cams, so plan for some head work while it is off. If you have a 70's head, you can keep it, otherwise consider changing it to a 70's head. To get more compression, the easiest thing to do is to mill it .060" or .070". If you do a complete rebild, consider "flat-top" pistons.
Read ALL of the "Sticky" messages in this and the High Tech forum. Especially the head swap article.
Finally, go to your profile and make some changes. Tell us where you live - you might have someone else close by. Do a signature that tells us about your car. It is important to know what you havein order to give you advice about how to add power.
Go to the web site in my signature and play with the compression calculator. You'll be able to see how the compression changes the power output.
Welcome to the forum - we'll try to help