Reply to "Solid Flat Tappet Street Cam"

I am fairly certain the 59° IVC you are quoting is based on duration at 0.050. The only reason cam grinders give valve event info based on duration at 0.050 is to assist the installer in timing the camshaft, because valve events at 0.050 have otherwise no bearing on an engine's performance. An engine's dynamic compression must be calculated based on the "SEATED" intake valve closing.

We rely on a cams "advertised" duration for computing "seated" valve events. The advertised duration of most solid tappet cams is based on 0.020 inch tappet lift; 0.020 inch "lash" at the tappet is equivalent to 0.035 inch lash at the valve (1.73 rocker arm ratio). So unless cams rated at 0.020 have 0.035 lash, their advertised duration will not be accurate, and the valve events computed with that data must be take with a grain of salt.

The limits of the production block under racing conditions is 450 bhp, 7200 rpm, and 8:1 dynamic compression. Race conditions means the engine is operated WFO down long straight-a-ways lap after lap. Sure owners get away with engines making more power, but not under racing conditions. A street engine is operated 99% of the time at part throttle, and an engine operated at part throttle is not producing anywhere close to its maximum compression. Drag racers get away with more power, but the experienced ones know that to go racing with an engine employing the production block making anything close to 500 bhp will require grout in the water jackets. Grout is a viable solution for drag racing, but not for circuit racing. Grout is not ideal for street cars either as it makes the oil run hotter.

Now that Tim Meyer is producing heavy duty blocks the solution is easy, the folks wanting to build high output engines should utilize one of Tim Meyers "Track Boss" blocks as the foundation for their engines.