I just purchased an Accel TPI Manifold at the Detroit Auto Swap Meet yesterday. I got it home, and looked inside, and there seems to be excess casting material in the runner. This is understandable due to the need to suspend the cores during casting. My question is...
#1. Is it going to be worth my time to clean up the ports to achieve a near perfect geometric shape and uniform wall texture with a die grinder.
#2. Assuming this doesn't inhibit airflow, what kind of surface finish am I looking to achieve? Because fuel doesn't atomize in the manifold, I would expect a near mirror finish would be best, but I'm open to suggestions. If not, what is the last grit that should be used?
#3. Anybody have before and after flow numbers?

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355 c.i.
Dart 180 Heads
Lunati 224/224 cam
Harland Sharp 1.5 rockers
Performer RPM Manifold
Holley 600 cfm double pumper
Hooker Super Competition Headers
Flowmaster Exhaust
Competition Engineering Sub-frame connectors
Super T-10
GM posi 3.42 rear
Hurst Roll Control
13.9@102

 

I flowed a stock Accel base versus a $250 ported base, and the difference was a whopping 2 cfm for the ported base.

At least the ported base looked better on the inside!

The trick is to increase the cross-sectional area as large as possible. Open it up as wide as possible.