The earliest ones were pretty famous for porosity.

The ones I've worked on of this vintage often have plenty of issues...... But that hasn't been one I've come across...... Yet.

Very nice work. Thanks for the post.

I guess I don't understand why these weren't recycled into 1,000 Miller Lite cans long ago due to the other head choices we have now?!

Amazing work

look great, and looks like it was alot of work.

Nice work!!

Remember when those heads first came out and I wanted some. Saw a set up at summit on a motor and was so disappointed on how they looked port wise, especially the exhaust ports. The valve guides were so huge and port clogging.

They were definitely not designed for a bolt on app, lots of work was needed to make them work great as shown.

Winter project Dwayne.

Thanks for the post Dwayne! Your work looks awesome as always. I love seeing these posts even if it's something that I will never have to worry with (hopefully).

Very informative. I have a friend that runs these type heads. He's running 6.teens in the 1/8 so they can make power. I'm trying to get him to go B1 because he wants to go faster and I don't think he has much left in these heads. His flow about 310 per Muscle Motors.

Thanks Dwayne

Thanks Fast, I'd never own a set, but interesting post on them

Dwayne is the best!! no detail goes missed. He straightened out my old stage 6s years ago.

When I saw the subject of this t read, I didn't know if I should or and watch the story unfold.

If the owner is using the MP Stage VI RB 4150 intake manifold, he needs to look into getting it reworked to really see the benefits of the improved heads. Out of the box, it leaves a LOT to be desired.

Brad......refresh my memory.

Doesn’t the stage 6 manifold really have MW sized runners, and is shrunk down where it bolts to the heads?

That’s how I remember it.......but I haven’t looked at one in several years.

If that’s how it really is, and one was looking for the “next step” in improving the flow into the motor........I would think opening it up, and then making the heads MW size to match would make the most sense.
I think you’d probably have to make a step up from the 509 cam to really see much benefit though.

Right, MW-sized runner entries squeezed down to even smaller exits than standard ports as cast... and a sh!tty transition from below the carb mounting pad into the roofs of the ports.

The owner -- IMO -- needs to rethink the build while it's still apart to make the combination "happy". But, it ain't my car, nor my $$$.

FWIW, Dwayne's last test on my old hand-ported Stage VIs:

Stage VI test #1 cylinder:
Lift -- Int / Exh (no tube)
.100 --- 69 / 53
.200 -- 143 / 108
.300 -- 213 / 146
.400 -- 262 / 181
.500 -- 293 / 211
.550 -- 305 / 222
.600 -- 307 / 231
.650 -- 307 / 237
.700 -- 307 / 243

And these were good enough for 600+ HP on a pump-gas 440 w/ the right combination of parts. However, the subject heads are going on something quite a bit different, from the sound of things.