Ive always thought as well that the mass produced heads got the cnc job because it was a mass produced. Ive never seen a head not respond to hand porting/blending as the finishing touch.

If one knows the casting well they can go past the so called safe limit that the mass produced cnc head.

With cnc becoming more the norm then not what about the motorsports that dont have cnc programs such as tractor pulling. Ive done many cast iron inline six heads that there will never be a cnc program.

As well as alot of the basics of head porting can help alot of heads to a point without a max effort and big costs.

Intake porting I think goes hand in hand with a max effort head porting job, this intake here in the pic is more or less maxed out runner and port wise and took a good amount of time to get there.

I like having the whole motor present to get the dead on exact port/head match which takes a good bit of time for just that process.

That is a classic article. Anyone who wants to build a race engine should read that article a few times.

I bet you could improve on most hand port jobs like that as well.

I think a lot of people think CNC heads are desighned on a computer, they are not (normally). They are a digital copy of someones hand port job, it will only be as good as the original hand ported head. I think a lot of CNC programs are too conservative to keep from cracking and such and speed up the process and keep people from sticking too much head on their engines sort of like how people put too big of a cam in most home built engines.

If some one made a real awesome port and had it digitized you could make CNC copys just as good. Most CNC heads just don't have that awesome of a port to copy.

Wish I could have gone to one of those classes. Looks like he stopped doing them after going back to R-M full time.

I'm just doing stuff like this in my spare time for fun(?). Not sure how long I could take it as a regular day job.

A cnc machine knows nothing by itself. If the cnc port doesnt move air then the digitized hand port lacked talent. And tool deflection? Really? Even if it pushed .010 it would still be a better REPEAT than a hand port.

My thought is there is no difference between CNC Ports versus Hand Ports. The bad part about hand porting is duplicating all the other holes. This took me about two weeks--not two days. As Mr. P Body states, having a good master is the key. If you copy a bad port, you wind up with a bad port. By hand porting, once you have a good intake and exhaust port, you have to humanly duplicate it by measuring; which is extremely difficult and very time consuming.

I have flowed many cnc ported heads. AFR heads seem to be right on the money with my bench. All others have fell short. As cast heads usually flow really close to advertised though. It seems to me that the superflow 1200 puts out higher numbers. Maybe it is actually more accurate though and my bench is just reading low compared to big box stores with mack daddy flow benches.

I really dont know what you guys mean by hand finishing a CNC port. I usually find no difference in flow sand rolling a port so mine are left like Brads picture above.

Btw, nice work Brad

I know of a small block engine that had its heads hand ported.
After they started leaking water, they were scrapped, the same model/ type of heads were given a CNC port copied from the same guy who had hand ported the original set..... In other words his program/ parameters were used
The results thus far..... Based on both sets of heads being on the identical engine and dyno, , at the same track, in the same car with no changes other than literally the heads ...It appears there is about a 20 horsepower difference in favor of the hand ported heads...... That was the difference on the dyno...... It appears the track difference is a solid tenth...... The CNC heads are without a doubt " smaller"..... But have more integrity regards the possibility of leaking.
This on a 700 ish horsepower engine

I will dig up some pics on my work computer late tonight of a cnc port before and after. For example as cnc programs vary and ive seen areas like where the bowl/runner meet that fair better with a cleanup and removing a bit of material. I myself never sand roll anything, just use a finer cutter in a die grinder and like that finish.

Also with the limited heads for small blocks to increase port volume and csa using a cnc head as a start helps since most are done in so called 'stages'.

Sounds like that small block wants a bigger set of heads

I know what your saying, i have a set of west coast cylinder heads "stage two" in my garage right now.

Yep.... The bane of 59 degree Mopar stuff since guys started offering long armed cranks.Huge cubic inch potential, but small 30+ year old heads designed to be used on sub 400 inch stuff at most. Big drink, small straw.

But worth the time. That is why everyone with a grinder can't port heads. Very tedious time consuming work.

Me too! I had Radar do my 440-1s, and recommend a cam. First time out, 8.96 at 3,000 lbs, 528 cubes.

l deflection IS an issue and depends on several factors. I wouldn't [censored] about .010.

If you can't match CNC heads by hand for repeatability you need a better porter.

I hand port to suit the combination, CNC can't do this, knowledge is power

I hand port because I can't afford to send my heads to anybody that knows what they are doing. LOL My hats off to all the professional porters out there. My cast iron heads took F O R E V E R to port to my satisfaction.

I will never claim to be a professional but I do enjoy doing it most of the time. I would never want to do it for a full time living. Just finished my Indy's at 11 pm tonight. Will do the final valve job and deck cleaning tomorrow and hopefully on the engine ready to go in sometime tomorrow. Who knows maybe some passes this weekend

Looking good!

. Thanks. Can't wait to give them a try