I don’t know and I’m not looking it up. What has the fastest lsx naturally aspirated run??
I am going to say it’s a safe bet that a windsor ford has ran a faster naturally aspirated et than an lsx based on the fact that you can get at least as many cubic inches out of a windsor block as an lsx block and I belive you can get more out of a windsor. Also you can get higher flowing cylinder heads for a 351w than for a lsx. So with the same or more cubic inches and better cylinder heads it can only be assumed that faster times have been ran with a 351w than a lsx.
To answer you next question these heads would be, Blue thunder, brodix - neal, yates sc-1, chi, edelbrock victor, tfs hi ports, and maybe a few others I am overlooking.
The lsx is a fine engine, I am seriously considering getting a c5 if I get a company vehicle and don’t have to worry about practicality.
BUT, GM didn’t reinvent the wheel with it and it isn’t any better than anything else. It’s a fine engine and as it is around longer better speed parts will be made for it. However there is nothing inherently better about it than any other small block engine.