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rockers?

343 Views 3 Replies 3 Participants Last post by  ShaunT
I was putting in my new roller lifters and noticed that i have 1.5 roller rockers. im new to fords, but on all the chevys ive owned they were 1.6 or 1.7

my ? is why would someone put in 1.5s and what should i have on it?
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If you have a Chevy rocker, the offset will be wrong and you will see that it sits on the valve off center.

1.6 is std issue. You could put a 1.5 ratio on the exhaust as that would give you a couple more inches of idle vacuume and a little better bottom end. Rocker ratio effects rocker geometry, so check it and change push rod length accordingly.

Unless the engine is starving for cam timing on the exhaust, the 1.5 ratio on the exhaust will help you.
If you have a Chevy rocker, the offset will be wrong and you will see that it sits on the valve off center.

1.6 is std issue. You could put a 1.5 ratio on the exhaust as that would give you a coulpe more inches of idle vacuume and a little better bottom end. Rocker ratio effects rocer geometry so check it and change push rod length accordingly.

Unless the engine is starving for cam timing on the exhaust, the 1.5 ratio on the exhaust will help you.
beast. i read this not knowing who it was, then guessed it was ShaunT afterward. the man knows his stuff.
Thank you.

Moving in a slightly different direction here, I see lost of people messing with rocker ratios in search of performance. There is nothing wrong with that move by itself. However, I get lots of people asking for "More" cam because they think they need it. It's real simple to do a rocker test and see if the engine really does want more cam.

This is what I tell drag racers and circle track racers alike: If you have 2 different rocker ratios, try the bigger ratio on the intake side first and see what the car does on the track. Forget what a Dyno says in this scenario. Then switch the big rocker ratio over to the exhaust and track test again. 90% of the time I hear them echo what I told them they would find which is usually that the bigger ratio rocker on the exhaust side hurt them, and the circle track racers almost always say that it hurt the car off the turn and it hurt my idle vacuume by about 2 inches. Therefore, it doesn't want more cam timing on the exhaust side. And that is how I answer them when they call up and say they think they need more cam. At least if they do, not on the exhaust side for their current RPM range.

With solid lifter cams, you can also answer the "does it need more cam" question by tightening up on the intake lash first, then the exhaust, and seeing the track results back to back.
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