Join Date: Dec 2008
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I did a speed run in 3rd this morning. At 60 MPH your turning around 2100. At 70 MPH your looking at 2400 RPM. I didn't push it any higher. But with the high idle on your trucks supposed to be set at 2750 that will give you an idea of what speeds to RPM you are using.
High idle means full throttle no load RPM. That is why I said to check your throttle linkage for full travel. If it is misadjusted/bent/hooked up wrong and so on. You might not be getting full use of the RPM your supposed to have.
Also how loose of a stock converter you have can change the RPM for a given speed to. Our trucks were equipted with loose converters from the factory. If yours is one of the real "loose" ones it would take higher RPM to maintain a given speed.
If you don't have tach's in your trucks you need to get a cheap optical tach to check the high idle speed.
93 W350 w/duals, fuel pin turned, 6X.018" injectors, 4" exhaust, 3" air intake horn, HX40/16, G56 /SBC Con-OFE, 307's axles' 2" skyjacker lift, B&W flatbed