2) - High Ratio Rockers – Thankfully GM made one thing simple…pushrod motors!! Stock GT/GTP cars came with 1.60:1 or 1.66:1 Ratio Rockers from the factory. There are a few choices that you have here to make some more power by letting those valves open more...
a) Modded Stock Rockers – ZZPerformance decided to elaborate on the efficient stock design for those wanting more performance on a budget. ZZP introduced the 1.90:1 Modded Stock Rockers. Basically, these rockers start out as stockers. The seats are welded in and ZZP re-machined them to achieve a ratio of 1.90:1. Great and easy way to add about 20 horsepower without having to change valve springs. As long as you keep your shift points at or below 6,000 RPM you will be fine. Anymore and the stock valve springs tend to float. Cost: $275+
b) Roller Rockers – If you want to upgrade your valve train and have the money to do so and are going the rocker route then Roller’s are right for you. Roller Rockers are a lot lighter and are much easier on the valves than the stock or Modded Rockers, but come at a price. Much more expensive than the Modded Stock Rockers for about the same performance gain. Roller’s come in the ratio of 1.60:1, 1.70:1, 1.80:1, 1.84:1, 1.90:1, and 1.95:1. Anything higher than 1.84:1 ratio is going to be needing valve springs to compensate for valve float as long as you are going to be shifting higher than 6,000 RPM’s. LS6(#90) or L76 Springs are great and cheap for this upgrade, but you will need retainers too. These are a great alternative to a cam budget wise and you still retain very stock drivability and some have even reported better gas mileage. Keep in mind you will benefit even more from a custom tune afterwards. Also remember that if you ever go with the cam route, you will have to sell the rockers as you can only run stock 1.6 ratio with a cam for the most part...unless you want to combine a higher ratio rocker with the cam you just installed for a crazy amount of lift. Cost: $399+
