i've been working on one of my 416 castings, and here are some progress pictures. Index of /images/porting i'm starting to work on the exhaust ports now. after the head is done, it goes to the shop to be tanked, and then re assembled. then i get to do it again to the other head. anyone wanting to leave some feedback, feel free!

Looking good! You're definetly getting there. Takes a long time, doesn't it? What's the full combo these are going on? Are you putting in bigger valves?

I've always been interested in the performance possibilities with ported 416s.

I would definately work somemore with the port matching because them intake ports look a lil too differant and it'ss hurt more then help. and theres quite a bit of rust in a couple of them, too help that if your gonna have them cleaned when done take some oil and coaat the runners as you finish to help keep them from rusting while doing the others if your not doin it all in the same few days

I think i'll have my 416s either flowed, or have the car dynoed (or both), in a few weeks here.

I never had a problem with rust with them sitting my garage, but once I spilled some water on them...


are you using carbide cutters? I hope so. I'd use 40-80grit sanding rolls in the combustion chamber and smooth it all out, then polish it with cross buffs. From the intake valve towards the spark plug you can lay back the wall to help flow. also deshroud the valves, even if you aren't going to 1.94 intakes, it still helps (ps, use 1.94 intakes).

I think you can open up the pushrod pinch area more. doom86 has a thread out there, where I think supervisor posted a good method for checking the thickness of the walls, so you don't punch through.

port matching is a bit of a waste of time, but that little corner that has the extra notch sticking out should be removed.

you can probably lower your valve guides more. Remember the guide should look like an air foil (in case you weren't aware)

what are you doing for your rocker studs? pinning?

mine are in the shop right now getting final assembly, i've got a few pics here if you want to see...


the bowls look pretty good, remember, widening there helps flow a lot, a wide "bowl"-like area where the flow has to change directions helps alot. Also the short side radius being smooth. Those are the biggest things to watch for.

going on a 350 motor?

Be carefull porting the intake bowls on the center two cylinders. The area betwen the guide and the wall closest to the exhaust port is VERY thin on the center two cylinder when compared to the outer two cylinders. I was able to get a 1/2" cabide in there with the outer cylinders but broke through to water as soon as I went from the 3/8" bit to the 1/2". So the center ports are a good 3/16" to 1/4" thinner here. It could have just been the set I was working with, but I bet it has something to do with the exhaust crossover.

the rust is just from sitting. as soon as the heads are done, they're getting cleaned before final assembly.

they're set-up for screw-in studs and guideplates. already had the valve job done for 1.94 intakes. kept the 1.5 exhausts.

they'll be going on a 305 with 1.6 rockers and a summit 1103 cam. i think the specs are 214/224 and .442/.465" lift. going to feed it with a quadrajet.

i think i'm pretty much done with the intakes, but i do want to do some finish cleaning. now for the exhausts. wheee!

There is no need to hog out that side of the intake bowl that big. You're actually destroying the "port bias" by opening up that side of the bowl exessively. Open it a little and contour the valve guide boss but do not try to make that side the same as the other (common wall side). The flow is concentrated along the common wall and roof. Concentrate your work there and enhance the port bias and swirl effect it creates.
Here is a pic of the setof 305 heads I just finished porting.