Well, it all depends how serious one would go
. Compression ratios back in the old days were kept quite low because of detonation issues. The more you feed air and gasoline to your engine, more heat is generated by burning it and that makes detonation more likely to occur if same amount of ignition advance is used. Today with computer controlled ignition devices you can retard ignition with knock sensor information or by tuning the charts by revs and boost amount. If compression ratios were from 7.5:1 to 8.5:1 in the eighties, now it's possible to use 10:1 to 12:1 easily.
Turbo size? Reed P. would be the right person to ask this about, but of course turbos from diesel engines are designed to work in lower rpm levels when compared with turbos from gasoline engines. Also huge truck diesels with engine capasities over 10 liters produce more exhaust gases to propell the turbos than tiny Y-blocks. Our next goal is to get two turbos that are good enough to 450+ hp each. Then it's different story how we get the Y to hold that stress what they generate. With the right size of a turbo you can eliminate the problem which we had when the single turbo itself was braking the engine with exess back pressure below the turbo flange. Also, the lag issue can be eliminated with correct sizing of parts used.
Stock or slightly ported heads are ok with low boost pressures. They might be ok with even lot more, but we had only 0.7 bar boost pressure at the dyno. But, the more you get them to flow, the more you can get hp from your engine. Today people are using well over 3 bar of boost pressure with their cars in drifting, drag racing and on the streets. Big pressures just generate new problems to solve with engines. Head gaskets must be different, overall sealing of the engine must be considered also, because sometimes that boost may get to the wrong side of the piston and blows gaskets and oil from the engine.
Also the pistons should be forged with high pressures and high heat levels. As you have red, we tried to save on everything, because we really didn't think it would work or last for a minute at the start 
. For the next bottom end we are thinking of better connecting rods, better pistons and a main stud girdle to hold it together. And of course changing to E85 as a fuel. That will keep the engine cooler and give us a change to use more ignition advance because E85 is not so prone to detonation.
As a camshaft I recommend mild grinds. In turbo engines exess overlap can cause problems. With a stock camshaft you can expect 30-35 percent increase in power. Wild cams may have crucial effects in torque curves.
What else? Just go for it and get some experiments. Electronic fuel injection is the key to succes but it can be done effectively with carbs too.
We are updating our sites with lots of pictures about our project so stay tuned. Some of those might be there after Monday when teros292 get all that stuff put there that I have mailed to him.
Oh, and yes... buy a book or two about turbocharging engines. easy and cheap way to avoid expensive mistakes and easier to read than from computer and the thousand different sites 
. And keep asking, we try to figure out the problems...
Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)