Ok, i have a simple question:
I'm wanting to boost a stock long block 5.0, but i don't know what year i want to buy yet. Its either going to be a 94-95 style, or an 89 coupe. What would be the safe limit for boosting on the two?

 

Anything under 8psi should be safe.

firefox

 

yeah 5.0's are tough they can handle 8 lbs safely maybe even 10 if everything is running perfect and tuned right

 

Its not boost that kills an engine, its detonation. Yes you can overpower the engine with the HP the blower will add, but reguardless of what most think, it can handle a lot. 4.6's and 5.0's are good for upwards of 450rwhp. Your engine isnt made 'outta jello! The best thing to do is to look at RWHP instead of boost but thats another can of worms.

For most people, talkin' boost is a little easier, so we will stick with that. A stock 5.0 could safely handle anything from 6# on up to 12#. When your boosting, tune is extremely important. Id say you could even go on up to 12psi without worrying about much of anything. As long as your tuned correctly within the engines HP limits, then no adverse engine damage should occur.

90% of the time, when someone does damage to a boosted application, its usualy because of a lean out condition. That either means a component failed, or the tune wasnt correct. With all that being said, standard boost for an entry lvl street kit is 8psi. AFM offers "Power Pipes" that usualy increase the boost by at least 2psi by unrestricting the inlet side of the S/C. Its like 2 free #'s of boost. IMO, I would run 8-10PSI and an AFM powerpipe. That would put you right at 10-12 psi while only spinning the S/C for 8-10psi. As long as you give the engine the fuel and tune, the S/C will reliably do all the rest for you.

EDIT: I just noticed you were thinking about an 89 5.0. The 89's came with forged pistons so that would probably be the better route. Reguardless of what you chose, the 5.0's weak link is the block. They dont like much over 500hp. D.S.S. has a new type of support system that prevents rear main cap walk before it starts, they have consistantly ran 650+HP through a stock 5.0 block with this setup and no problems or sign of damage. At that power, youd have to forge the internals anyhow.

 

how u boosting it