Performance Gain Stock Rockers to 1.5RR?

[Billy Nees]

Dan, on my 307 (definitely not an LT-1!) going from the stamped rockers to roller rockers was worth absolutely nothing.

[Mark Yacavone]

Originally Posted by Billy Nees

Dan, on my 307 (definitely not an LT-1!) going from the stamped rockers to roller rockers was worth absolutely nothing.

I have seen this right on the dyno too. Another "it depends".

[SSDiv6]

Originally Posted by Mark Yacavone

I have seen this right on the dyno too. Another "it depends".

Mark is correct. It depends on the engine, especially on the type of engine, horsepower output and RPM. A higher horsepower/high RPM engine will benefit from aftermarket rocker arms due to reduced rocker arm deflection and stabilization of the valvetrain. Since the liberalization of camshaft specifications with more radical lobes and high pressure valve springs, a stamped rocker arm will have a very limited life.

[Billy Nees]

Originally Posted by SSDiv6

A higher horsepower/high RPM engine will benefit from aftermarket rocker arms due to reduced rocker arm deflection and stabilization of the valvetrain. Since the liberalization of camshaft specifications with more radical lobes and high pressure valve springs, a stamped rocker arm will have a very limited life.

And since we're on the subject, the"aftermarket rocker arms" that "reduced rocker arm deflection" and allowed the "stabilization of the valvetrain" ALSO made it a necessity to port your heads and intake if you wanted to stay competitive. In other words, in the good old days, you could either run well and keep your stuff together for a 7 round race or go fast and gamble on when you were gonna break a rocker.

[GUMP]

I ran treated and coated stock rockers that we machined to work with a 7/16 stud on my LT1's. I saw no performance gain going to a roller rocker. Limited travel lifters was a different story.....

[Larry Hill]

The truck engine liked the 7/16 studs they had less deflection than the 3/8.

[Dan Fahey]

Building the Pure Stock engine replaced the 3/8 with a 7/16th stud figuring it was a good bit stronger. Cannot remember the racers name he sent me his modified LT1 SA Stock Rockers. Bought new 7/16th ball, installed them and runs smooth.

Like Billy said, he saw no gain going to Rollers.

Many of our Impala Club members stayed with the Stock LT1 SA rockers installing the popular HotCam with no problems. Figuring the 3/8th Stud was not much of an issue to begin with.

Wondering if someone makes a 1.5 SA Roller Tip?
Use the 7/16th ball and trim the sides up to fit.
Would stop all side loading on the valve and guide.

I have set of original GM SA 1.6 Roller Rockers.
Then again they use 3/8 stud.
Saving them for a project.