Running mismatched rocker arms.


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By Eightydeuce - 14 Years Ago
Guy's,



I was wondering what concerns I may have with running mismatched rockers? I'm running a 312 in my 55 which was rebuilt before I bought the car, today I had the valve covers off and noticed one side has the 1.54 ECG 6564 rockers and the other side are the 1.43 575-1066 rockers. So far I've put about 7,000 miles on the engine.
By Hoosier Hurricane - 14 Years Ago
You are doing no harm to the engine.
By texasmark1 - 14 Years Ago
got a similar deal... jamb nut adjusters on one side and the kind with a locking nut on the other... so far so good but was wondering about this "mismatch" since I discovered it...

Mark

By YellowWing - 14 Years Ago
I had the same thing 1.54s on the drivers side 1.43 on the passenger side. Car always wanted to turn right till I changed them Wink

Actually I also see no problem with this. If the rockers and shafts have no wear you could install the 1.54 on the intakes and the 1.43s on the exhaust, but probably too late for that now.

By Ted - 14 Years Ago

Mike’s suggestion is a good one.  Although for the most part, you’ll likely not feel the difference in seat of the pants performance, the rocker arms could be repositioned on the shafts so that the 1.54:1’s are on the intake valves and the 1.43:1’s are on the exhaust valves.  That would put all the cylinders on equal footing although the change is subtle.

By DANIEL TINDER - 14 Years Ago
Just curious, but is it routine to favor the intakes with more lift? What situations might indicate the reverse (oversized carb.& headers maybe)?
By Ted - 14 Years Ago
DANIEL TINDER (4/1/2011)
Just curious, but is it routine to favor the intakes with more lift? What situations might indicate the reverse (oversized carb.& headers maybe)?
The intake valve on a stock or small duration camshaft typically sees more benefit from a faster opening rate than the exhaust valve.  If the exhaust system itself is highly restrictive, then the higher rocker arm ratio may be of some benefit on the exhaust valve instead.
By Eightydeuce - 14 Years Ago
Thanks for the help, I ended up swapping the rockers around and using the 1.54's for the intake's.