The heads were taken off the engines before they are ever started. When Herrod do thier engine builds, they buy complete engines, then remove the heads, and put on bigger/better items. I was told that the heads are compete, and unused.
As for the cam, i have no idea what SVO cams are like. They are big in america, but all the big guys over there have custom billet items, and they are expensive. I have never done a price comparrison on crow to SVO, for the simple reason i have has a crow cam before and was very happy with it, and i have seen them used in other application, and have not heard a bad word about them.
As for cost, if your pretty handy with your tools, you could assemble the engine your self, just get a really good torque wrench, ring compressor, plastigraph, and your usual socket set and associated tools.
It cost me $130 to get the bare block bored, honed, and chemically cleaned.
Pistons should cost about $300, and about a further $150 for a ring set.
You will need to get an engine shop to press the pins into the pistons on the small ends, but that should not cost a whole lot. You could get new rods with floating pins, but thats more money, and you dont really need them.
The rest of the assembly is pretty easy, the heads should come with torque settings and torque order for assembling the bottom end, cam comes with very detailed instructions, easy to do, the rest of the bottom end is very easy to put back together, just have to have the torque settings right.
Its not really that hard to put an engine together, it just takes time, patience, and common sence.
I think if you put the enging together your self, bought the GT40P heads, the cam, some new lifters ($110), pistons, rings, gaskets and ARP bolts, you could probably get out of it for about $2500.
I would also recomend you buy an engine stand($100), so you can roll the engine over for toquing the mains.
and have a look at the price on thier bits, thats where most of my stuff is coming from, and they are very helpful on the phone with support too.
If you wanted to spend the $4-5K as previously mentioned, you could add an edlebrock, or trickflow, or whatever upper and lower intake manifold and bigger throttle body as well, you will have a very neat little package that will blow away most people that want to line up next to you.