USED for ~ 20K miles and they are in great shape. I had them installed on my grand prix for several years with no issues. No tuning required and no stiffer valve springs are needed. I ran them over 6200 in 1st gear with no valve float. These are the largest you can run on a stock valvetrain without floating your valves.
Awesome mod worth atleast 10-15 horsepower and a noticable increase in upper RPMs. The gains on GTPs are even more. NA I ran several stock GTPs with these.
$250 pics if needed. you cannot use these with an aftermarket cam. All you need to install are new rocker bolts and valvecover gaskets
here’s the link for new ones. apparently they don’t even have 1.8s in stock anymore
https://www.zzperformance.com/grand_prix/products1.php?id=129&catid=104