[fiveohpatrol]

you can use a MSD 6AL or digital 6 ignition box. This way you can set the RPM limit that cuts out spark sequentially, not fuel. You can either set the total rev limit to 5000, or you can wire up a "2-step" limiter that is only active when you're pushing a button. When you release the button, the limiter will increase to another limiter that you've set so you can go higher than 5000 if you want.