My car has a 305 tbi in it. About 3 years ago I started buying parts for my 350 build. I have ran out of money for now and I'm sick and tired of the 305. I was wondering if it would be worth it to put the parts on my 305 because I changed my mind anyway on my build. What I got for parts is, Edelbrock Performer RPM heads, Performer RPM cam, and a few other small things like new distributer & timing chain. The heads are 64cc chamber heads and I'm just wondering if this is a good idea or if it won't make much more power because of the 305. I know I'm still going to end up spending a little more money because I'll need rocker arms and a few others. But my biggest question is will the stock injectors be able to handle the mods. Please give me any input or advice you can! I still plan on the build but I want 500+ horsepower plus I figure right now is a good time to get my suspension work done also.

you want 500 hp out of an 305 tbi

64 cc is way to big and there is nothing you can do to make them fit. you cant mill them down because your intake will not be at the correct angle.
but everything else will fit.
you can get a set of 081 heads and port and polish them and set them up for the cam. if you have ss valves you can use them in those heads, just make sure they are 3 angle cuts. those heads will handle .510 lift and you can increase that by playing with the springs and offset the springs or cut the seats down.
but you are still going to have to pull the engine, clean it up, check the mains.
most everything else will probably fit.
but there are some real hot head people on the board, just pray they see this and they can walk you through an entire process.

I think he means to say that he eventually wants to build a 500hp engine, but for now he doesnt have the money, so he just wants more power than the 305 has now...correct?

oh ok

Not true. It's about .006" per cc, or .036" mill. Have the machine shop that mills the heads mill the intake manifold as well. The heads and intake will be a matched set from then on.

You can also mill the block so the intake fits, but it's generally not recommended.

...wow! I guess I didn't expect that. First, thanks am man for clearing that up. I thought it would be as simple as swapping out what I already have and gaining more power. I guess I don't understand what makes my motor not work. What size chambers do the factory heads have? I'm not going to spend a bunch of money machining the 305 either, that would just defeat the purpose of saving for my build later. I absolutely understand what you're saying though about checking everything over even though my car has fairly low mileage. I guess I might have a pair of heads and a cam for sale.

Factory fbody 305 heads are 58cc.

Since your new here, check out the TBI specific forum on here. I'm sure that if you use the search function in there you will find info on this site from people who have had very similar questions about making power in their cars.