how much boost?

i know 5-6PSI is a safe limit for stock motors. Then i pulled out my 5.0/4.6 tech guide magazine i bought and they were running 10PSI (with a cooler to cool the incoming air) on a stock motor with 100K miles on it. It dynoed at 333HP and 358Lbs of Torque. I was wondering if this was safe for a motor? and the transmission? Especially if its just a street car? If it is safe, i think i'll skip the entry level blowers and wait till i have enough money to get the 10PSI ones. Thanks for your help!
 
I think if you run an intercooler, or after cooler, you will be able to run more boost. I'm not sure though. I know on my brothers car he can safely run more boost if it is intercooled. I think the reason is because you don't detonate as easy. I could be 100% wrong though, anyone else care to prove me wrong, or back me up?
 
Well 10 psi on a stock motor should be no problem at all intercooled or not intercooled.. The trick is you need to get it dyno tuned to be near 100% safe.. If you just go and through a blower on anything can really happen.. I had a Procharger D-1 sc with intercooler (which is for sale right now hehe) on my completely stock long block.. On mods on engine were TFS track heat intake, pro M 75mm bullet maf, and BBK 70mm tb.. Also have 42lb injectors as well as 255 in tank pump.. The kit also had FMU and inline fuel pump.. Well I was pushing 10lbs sometimes would see 12 at most depending on cold day.. I had my car dyno'd in september of 2002 and it made 383rwhp and 392rwft/lbs.. Now remember all on a stock 302 long block with 80,000 miles on it.. The hp #'s would actually be more since no cold air was going through intercooler, only air blowing from a fan.. So it could be anywhere from 380-400.. Never had any problems with car at all after getting it tuned with the chip.. All tuning was done at LaRocca's in New Jersey