Magnum 300 crate engine - how should it go when tuned up right?
- Fill up with 93 for tuning
- Verify TDC matches balancer markings
- Inspect distributor mechanical flyweight and vacuum advance operation
- Obtain 34-36 degrees of total advance with the vacuum advance disconnected and plugged. Reconnect to the correct manifold vacuum port after setting total time.
- Set idle speed and mixture simultaneously to obtain maximum idle manifold vacuum
- Ensure carb power valve is the proper size for your engines vacuum numbers
- Adjust the carb accelerator pump circuit to remove any lean stumble or bog down. I like make it the leanest setting possible and then enrichen it til the lean stumble is gone.
- Set main and secondary jetting by inspecting plugs, by MPH and ET, or by wideband o2.
Wideband o2 helps out with a lot of these adjustments and is relatively cheap these days. Will save you time and money in the long run.