well, let's start with saying that I'm building my first engine too...

that said, I think you're in the right forum here, because I also had some tech-questions wich were all answered thoroughly and quickly here...and probably will have some more...

now to the max HP...
I've seen questions like that very often here and as you might expect, it is very hard to guestimate a HP result, before even knowing what components you're going to use.
I'm only starting putting mine together, having collected, matched and machined all the parts and I still don't know what power it will yield when ready...guestimate is somewhere between 450 and 550...but that's still a guess.

Since you already starting off with a 410, you're a small bit ahead of me with my 390 (20 cubes , duh...and some parts)...from what I understand, a 30 overbore is a safe and often practiced refreshing of the main block. (becoming a 416, how nice!)

Pistons is something for you too look into, cause i believe you're engine ran a 10,5 to 1 comp. ratio and while they're offering quite some replacement pistons for this block, I believe these are for truck use mainly (yielding only 8 to 1 cr), so find some that give you at least the same ratio or even higher if possible (what gas?Mild or agressive cam?)

Besides the edelbrock performer heads, you've got the edelbrock performer intake (or like I have , a weiand), plenty of those you can find on ebay...if you decide to go this way, you'll have a lot of weightloss on your engine programm, because it's all aluminium!

I used the intake gaskets to do some portmatching on both the heads and the intake...simply using a small dremeltool...this won't cost you much (only time spend) but will give some gain in HP, how much is unsure, but hey, it didn't cost anything!(but don't go too far...)

A nice thing also; shorty headers...these flow much better than the stock exhaust manifolds. But they have to fit your car... I found some for my T-bird at FordPowerTrain, maybe they have some for your application too?

With cam and lifters I think the safest way is to order them as a package, something like Comp.Cam or equal, keep in mind that comp.ratio and driveability are some issues you should considder, while making a decission on this...(street use, like me, I shouldn't go too wild...)

ignition, still using the stock singlepoint ditrib.? Look for a dualpoint conversion-kit at the least. Already dualpoint, leave it there! Completely computerised, single cylinder monitored sytems are possible, but hey, we're not in the F1 business, are we?

when keeping it below 6000 rpm, your stock rods probably will do fine. For higher speeds go for the H-beam (pricy!)
I would advise agianst it, because the large stroke restricts your engine in the high rpm range...it's more of a torquer, but a good one!