Stops pulling around 5000 rpm in low gear. Has a 400 small block street/strip build with a radical cam. 3200 stall, 350 turbo transmission. 410 rear end. This issue just began. Any suggestions to the cause of this issue.

 

Valve float?

 

Thanks for the reply. I will look into that. It has a Lazer cam part #2900116 and Dart heads. Any suggestions on how to properly check for Valve float? Or properly setting the valves springs. Thanks again for the input.

 

If this just started, how long was the engine running without the problem? What RPM were you routinely turning? If it ran fine for a reasonable amount of time, may be a sign of worn out springs. Who selected the valve train components to go with the “radical” cam? Heads probably have big valves, particularly the intakes. Cam probably has steep closing ramps. Critical need to optimize the combination of valve train weight and spring pressures. That’s about the limit of my knowledge. I left the selection of valve train components up to an experienced engine builder.

Extended valve float can sometimes be diagnosed from damage the tips of the valve stems and seat surfaces.

On the other hand, has the performance of the fuel system dropped off, causing it to run out of fuel? Has an ignition component begun to fail?