HP & Torque numbers for Cross Ram

[ERA 626]

Originally Posted by olddog

Correct me if I'm wrong, but speed density also does not handle radical cam profiles, as well.

600 HP with a single carb on this engine, no problem. Putting on the 8 stack with speed density and wanting it to drive nice and friendly may be a challenge. I know there are plenty of people on this site who have done some of this work in the past. I didn't follow it closely, nor can my mind retain things well at this stage of life.

I know in theory single pipes into the cylinders and single pipes out of the cylinders should allow a radical cam to idle smoothly, as the reversion flow from one cylinder does not disturb other cylinders. However back in the real world, the reversion air flow is pushing fuel laden air out the horns, causing an explosive haze to hover over the engine with webbers. Then the fuel laden air is sucked back through the webber again making it near impossible to get the AFR correct. So getting these engines to run well at lower rpms requires milder cam profiles.

The short air path of a nice 8 stack lends itself to high rpm air flow, but at the same time requires a cam profile that does not help high rpm air flow. This is where super good flowing heads come into play. Good heads do not require as radical cam profile to flow at higher rpms. I'm not certain there are tons of heads for the FE that will do that. I'm not saying the combo cannot be found. However this is not likely to be a easy case of tossing parts together and getting it to work.

Maybe I should explain more, The builder said it was "stupid" because I was thinking of building a 496 CI FE, We can easily do this with the 482 4.250 bore motor. The intake am having made is not really an 8 stack it is more of a cross ram with longer runners that start big and reduce down to the size of the port on the head. My builder has done several of these on SBF pantara projects they are amazing built by Moorison in New Zealand. He explains the port velocity being like a supercharger. The design includes a common vacuum plenum under the runners. Yes we will most likely loose the rumpy Idle (reversion) a little bummed about this.

This build is going into a Brand new CSX car.. The build will be as much fun as the drive...