gdmiller123

Im going to be in the market for a c6z in the next 6 months ish so im just doing a little browsing around. Ive had two highly modified c5z's so Im not new to the vette game. One thing ive noticed is there are quite a few lower mileage (under 50k, some under 20k) c6z's with swapped motors to a lsx based block or erl ect. Is there a reason for this? I know about the valve train issue and one could assume that maybe they had a valve drop on their stock motor thus causing the need to build a motor but none of them mention that. Or is it the fact that you could get such good money for a stock ls7 that it nearly, or does fund the full build of a badass aftermarket block motor? Just curious if anyone could shed a little light on it for me.

C6z06man

I'm willing to bet most are because of a failure whether that be a valve (which obviously is a real problem) or other failures. The LS7 is a great engine and if not going crazy with it there's no reason to swap it out in my opinion.

gdmiller123

I'm guessing that as well. The plan with mine when I get it is to do head/cam pretty much immediately to deter any valve related issues.

C6z06man

I and many people on this forum will at least recommend checking the valves before/as soon as you get it. If bad you'll have to pull the heads anyway and doing a cam isnt that much more work. So a lot of people (including myself this winter/spring) do a cam also.

gdmiller123

Yea that's why I planned to go ahead and do head/cam pretty much imidiatly. I currently have a head/cam c5z so the work is not foreign to me. Thanks for the reply.

Unreal

Most of the time it is cheaper/easier/better to upgrade when the factory motor fails, so you are probably right.

gdmiller123

Are you saying before it fails or after their stock motor fails?

Unreal

Either. I pulled mine before it failed, sold it, and did a LSX block. With the high failure rate of LS7s they are easy to sell. I had guys fighting over mine and should have sold it for more. There was a few post the other day of people looking for stock ls7 motors to replace dead motors. You can get good money for a running one, and if you are going to do a >700hp build it does work out to sell it and build something aftermarket.

gdmiller123

Makes complete sense. They are perfectly fine in the 600hp to the wheels range correct?

silvrhand

a true 600rwhp takes a bit of work that doesn't seem to be worth it for the last 50hp, you can do full bolt ons and get a strong 550rwhp, and after that you are traction limited anyways. To get 600rwhp you have to start making sacrifices IMHO.

Unreal

600-700rwhp just fine. ^^^ is talking NA. Blower 5-6psi, 600-635rwhp cake. No sacrifices besides the cost of the blower.