i know i will have better launches but will it kill my top end speeds. i have 3.23s right now i think and i have the z rear end is it worth it to swap. i do like the lsd/disc idea but i still want to go 80 with out red lineing thanks

 

I seriously doubt you will notice the difference. A change from 3.23's to a 3.42 will increase your RPM at any given speed by 5.8%.... so there's absolutley no chance of "redlining" it at 80mph. And I doubt your top speed would be any different.... the extra RPM will give you a bit more HP at any speed and may even increase top speed.

What car do you have now? Is it a "Z28"? Why do you think you may already have a "the z rearend". Sounds like you are upgrading from an open rear and drum brakes, which would suggest you are starting out with a base 6-cyl model.

Add a "signature" with basic info about your car, like year, model, tranny type, and any major mods. That will help people answer your questions.

 

i have the v6 modal and the past two years i have been putting together a new engin for it i have a 383 stroker that i am trying to build up and i have the wireing/transmission basicly every thing to do the swap but until i have it all finished i just want to have a tiny bit more umff in the v6.

 

3.42 gears will not kill top speed (it'll be lower though), and will not make you redline at 80. You will be in second shifting to third even after that. You are still going to have a top speed of 125 or so in third with 5500 rpm.