Thought some of you might find this picture useful or at least interesting
 

This is a 16 head I cut in half with a hack saw to learn from for porting purposes way back in the 80s. I got lucky doing it with a standard size hacksaw and had to cut halfway from each side hoping they intersected. Got lucky with the guide mostly intact and the intake valve can be held in place for valve train mockups, and misc visualations.

That must of been some arm work out!

Did you do it all in one shot?

Here’s two shot’s of a ported 290 cfm 16 casting, but the earlier one with the air injection boss still part of the casting.

You see how far I ground into the roof and exposed a lot of the rocker stud hole.

Thanks for saving the photo and posting it!

That certainly shows how much metal you can take out of that troublesome inner bend.

I have a nice set of ported 48s that are ground through on all the roofs and patched with epoxy and brazing. I never had them flow tested but I did run 10.50s @ 126 mph with them and a big solid flat tappet cam in a 3300 pound car (less driver) I drive to the track. Your 16s flowing 290cfm ..thats pretty damned good .. what numbers do you run with them?

I cut the head in half in one day at work using my breaks and lunch. So it took me a little less than an hour of hand hack sawing. The head I cut in half was being ported but got a hole in it in the bowl close to where it meets the guide at top of bowl; hitting the water jacket. You can see in the picture that is the thinnest area from that cross-sectional view. It wasn't really fixable so I cut the head up to learn from it and then found a set of small chamber 48s off a 350 HO (64cc chambers) and ported them. I finally got a set of Kauffman HighPorts so my 48s are now retired waiting for a backup engine build. Or if someone wants to buy them for the right price I might be able to break my attachment to them.

Only about a hour, that's surprising!

These 16 heads took a 455 in a early Bird that was 3450 with driver into the low 10.20s

I had custom 2.14" valves made up so I could run 45 degree seats and not sink the valve, also by doing that was able to get most of the upper part of the valve bowl quite big as you can see in the one photo.
This allowed me to get a stout 155 cfm@ .200" lift which really helped the VE numbers.

I have one of those cut-apart #16 cast iron heads on a shelf in my basement.
At least 25 years old.

Tom V.

what is the stock dimensions at the pinch point. and how much can i safely remove to make it larger? i have 68 number 16 heads.

Before I give you my answer I need to ask where in the intake runner are you considering the pinch point to be your asking about?

For me and a whole big bunch of other folks who port heads, it’s the area of the smallest amount of square inches.

Tom, might you also have it cut apart in a way that exposes the intake port side of one of the center exh ports?

the push rod bulge. im considering a gasket match 1233 gasket. as you can tell im a novice at porting. is there a specific dimension i should shoot for? those pics. helped me alot. thanks for the response and your help.

If you want a head cut up, I have a 900lb, 10x18 Johnson bandsaw that would be great for this purpose. Built in 1946, no less - like a few of you old bastards.

Let me first say that unless your intake is already matched to the 1233 then don’t bother!

A D port head can be reworked to flow 250 cfm before you need the added area of the 1233 gasket.

After you do the gasket match on the common wall side of the port then You can safely go to a with of 1.064” at the apex.

When grinding you want to try and keep the out bound side of the bulge a sharp edge / lip verticaly.

This will help to keep the fuel in the air mass atomized like it should be.

Opening up this pinch area depending on how much valve lift your running( and also if the rest of the intake runner) has been ported might only pick you up 2 to 5 cfm, but the main improvement will be your motors power band will be wider due to the air mass not having to contract and then expanded once again.

If you go to post #2 here and click on my second photo you can double expand it to see that I ground back right to the .030” wall 1/2” OD brass tube .

If your careful you should be able to come within .040” of that.

My Anonymous, I am 11 years younger then that Bastard age bar but I will still accept that title, lol!
thanks for the offer, but where do you live?

SW of Dayton, OH. If you like our cows and corn, you'll love our meth!

the cam i'm using is the 041,the intake has been already gasket matched. 230 cfm would be fine i think. i'm just trying to get things to work well together.thanks for the quick response

Well if your intake is already gasket matched to the 1233 gasket then you need to take that 1/8” of taller roof height 1.5 inches into the head runner so the neck down back to stock size is not as severe and disturbing to the air mass!

yeah, that is what i was thinking. thanks for your help, greatly appreciated.