Right now I am running a 4.25 pulley on a D1SC on a internally stock 5.3.It peaks out at 9-10 psi of boost at my shift points.What would I see boost wise if I drop my pulley down to a 4.00 and is this to much for a stock 5.3?

 

I would say that would be the limit to stay on the safe side but a good tune is what's going to make or break how much psi you run.

 

Which would be the limit the 4.25 or the 4.00?

 

That would most likely net you around 13 psi if you are now seeing 10. I wouldnt do it on a completely stock 5.3. Put a meth kit on it then switch to the smaller pulley.

 

wow. I ran the 4" pulley on my 4.3 with the prochrager and i only seen about 9psi. You have a full liter more displacement and you are at the same boost. ?????

 

badnoma, did you have the same blower? did you have a cam or other internal work? did you have aftermarket exhaust or headers? all this will decrease boost levels but increase HP

 

I don't know if ya'll remember my last set up. Bone stock 5.3, D1sc 4.00 pulley, 3-core intercooler, 44lb. inj., 255lph intank, custom 4" cat-back, tuned by MTI. It made 12 psi on the dyno and 14 psi on the road at the 1-2 shift. Made great power for two days then BOOM! Killed the #7 piston. I think it would have lasted longer if the tune wasn't so aggressive. Power was 440rwhp and 450 rwtq.

 

I'll stick with the 4.25.thanks