Ported my Super Victor today

[Killer6]

Oh, I'm not defending recent poor QC by Eddy, just addressing the "mixed blessing" of the smaller port. I have an RB RPM intake that was purchased over 10yrs. ago, never
got used, for hood clearance reasons among others. Dropped it on a 440 I built for this customer's car in '94, 452 heads port matched to the gaskets, MP .017" shim gaskets.
Looked inside w/a scope, nearly as perfect as could be, every port top to bottom. It sucks to deal with these issues now, & really boils down to carelessness in preparing for
the pour, the patterns haven't changed for most so......................

 

[mopowers]

If the intake is bigger than the port, there is some reduction in air speed right at the mismatch, but it was minimal. When the intake is smaller, you can see 280-300 FPS at .500 in the port. At the flange I have seen zero.

I didn't spend nearly enough time sorting stuff out for velocity and I wish I had. Thinking of buying another bench so I don't have to drive 3 hours to test anything. If I do, I will certainly spend more time with air speed measurement, because IMHO, controlling air speed and direction is 90% of the battle.

I guess I wasn't clear. I meant to ask- when you said you've seen instances where there was zero flow for an inch when the intake ports were smaller than the head ports. I'm wondering how that translates to power on a dyno vs having the ports matched.

 

[yellow rose]

I guess I wasn't clear. I meant to ask- when you said you've seen instances where there was zero flow for an inch when the intake ports were smaller than the head ports. I'm wondering how that translates to power on a dyno vs having the ports matched.

The sorry answer is it depends.
It depends on how the mismatch came to be. Is the runner smaller all the way to the plenum? If it is, the power drop will be so low in the RPM you might not notice it.

If the runner is bigger at the plenum and smaller at the flange, and you make the intake port bigger, but not as big as the port, that is a pretty big power loss.

The biggest power loss is a good to great flowing port, with a port matched intake that makes the intake runner an hour glass shape where the runner is bigger at the plenum, tapers down until it gets to the head and then opens back up again.

As for exact power numbers, again, it depends. On a 300 HP engine, its 10-12 HP. On a 900 HP B-1 engine I did the freshen up on it was 40. Just correcting the port alignment and making the runner match the head was 40 HP at 6500 RPM.

 

[12many]

Feels like Déjà vu reading this, but find it worthy of revival. Talking about Edelbrock quality etc.....Starting on a basic cleanup myself on a Victor 340, opening the port/runner windows up, to match the heads.
Then removing slight bulges from 7 runners on the short/inside wall (indicated in red) located about 1” in. The #6 runner has a nice radius which I’ll replicate in the others. Then the plenum. Lots of work needed, as many know. Very bulbous, bulged dividers as shown. Gotta fix that, thin them out a bit, looking for nice contour/radius’s, and then radius the flange/opening into the roof of each runner.
Yeah, pretty sloppy casting overall