The 332 cc 3xO is not that small. The pour cc might seem small but the 2.300 intake valve and flow numbers suggest otherwise. In this rpm range should work well. I'm interested to hear what RM builder had to say.

I'm interested to hear what RM builder had to say.[/QUOTE]

Must be top secret.

What intake are you running?

I am using the ACCEL 74202C SuperRam Intake Manifold
oval port.

In matching the heads to scale of the engine it is necessary to evaluate the relevant engine parameters. For this example, looking at displacement, engine speed, and V/E will supply the necessary data.
• 604 CID
• 3000-5500 Power band
• Low compression/low RPM
• Hydraulic roller camshaft with a stated max lift @ valve of .650”, which after deflection may net .620”@ the valve on a good day. As long as the head shows no signs of backing up prior to ~ .750”, any flow values > .625” provide no relevant data to this specific application.
The graph below illustrates the flow values of four different Brodix heads, three of which are oval ports, in the same family as those used on Kens 604 CID.
To keep the comparative head selection valid we will use only Brodix heads, as that is Kens head selection, flowed on the same bench (Brodix), by Brodix. This will mitigate any discrepancies due to operator or equipment. The four heads are:
• BB-3 XTRA 363 cc
• BP BB-3 XTRA O 332 (CNC Ported/50° Valve Job) As used
• BP BB-3 XTRA O 351 (CNC Ported/50° Valve Job)
• BP BB-3 XTRA O 365 (CNC Ported/50° Valve Job)

When viewed graphically it is evident that there is no advantage to utilizing a cylinder head with larger port volume and increased CSA as the flow value increase at our data point is negligible. What the heads pour may not reflect the CSA of the port; however, in a comparison of the same series heads by a common manufacturer, the comparison is relevant.

The downside to increasing the CSA of the port:
• Decrease port velocity
• Fuel falling out of suspension/atomization, wall wetting
• Decrease V/E
• Increased column air speed (of a smaller port) provides increased energy and inertia for cylinder fill, with less reversion potential.
• More energy expended in initiating column motion
The person responsible for cylinder head selection in this application was absolutely correct in their evaluation.
Bob

niiiiice Rob , sounds like Kens well on his way

Bob,
Thanks again I could have really screwed this up with out your help.
Ken

any progress updates Ken ???

Thanks Bob for the technical analysis of port size. I was hoping you would post some info on what cam specs would also work best in this applicaton. The Brodix 3X Ovals are a good flowing head for the money.


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