Hey thunder550, Did you change your shift points, and did it help any. I know my trucks shifts out at 6000 and I would be scared go to much more than on the Stock motor cause she screaming there with the Procharger. I wish i shift about 6300 or so, but that will be after some internal modifications.

 

I did go up and it was great till I overspun my alternator and lit it on fire. I dropped all three shift points back to 5900. I have an aftermarket alt with a smaller pulley so it spun faster than a stock alt would. I now have a Delphi 145 amp in....may go back up but I will have to see if anyone else has had problems.

2nd gear would take me up to over 90 mph though with the 6200 rpm 2-3 shift, it was pretty kick ***. I want the higher points back...we'll see...

 

You have to take into consideration the strength of your bottom end, valve train, cam profile and the amount of rotating mass you have slinging around down there.... you could possibly do 6300 RPM's on a 4.8 but I wouldnt try it with the 5.3 or 6.0.... remember the good 'ole days of the 283 in the Camaros? those were some screaming little engines that produced high RPM numbers and great high end HP because of their short stroke. Much like the 4.8. The bigger more displacement you have, the slower I ould shift out of it unless you have the bottom guts to hold it all in one piece. I always think about the longevity of whatever I am building too. you may be able to get away with 6350 in a 5.3 but I wouldnt trust it to do it too many times and still keep your parts out of the road.... Just some thoughts... I would say safely for the blown 5.3 would be something like this:
1-2 6200
2-3 6150
3-4 6050

all these things depend on your tune, cam, bottom, and valve train....
-internal weight is a sunuvabitch...

 

I totally forgot about this too....

dyno referencing on your shifts ensures the best possible settings for your individual engine and mods. This is the way I would go if given the option.

 

I don't think the bottom end would be a constriction even at 6600 on a 5.3 at all, even pushing a good bit of power. I'd be more worried about the valvetrain than anything. Just make sure you got the springs, and spin that thing as high as you care to, within reason of course. I'd try and keep it under 7000.

 

dont forget tow/haul, my 1-2 shift is at 5600 normaly and at 6000 in tow/haul
I asked allen to set that up and its fun.

 

i have try to spin my 6.0 to 7k and it just stops pulling at r around 6600 my shift points r @ 6400 but i have been shifting on a 6600 chip.