How To:Basic Cylinder Head Porting for Beginners

Thanks aero! Looked that up and learned a lot today.
However I could not find a calculator to solve hydraulic diameter for ovals like the hemi port. Lots of formulas to calculate it though.
I did find a table for squared corner rectangles. 1.5 x 2 and that was a 1.71 round pipe.

I'm going to work on this some as tonight's busy stuff. I'm going to draw up the port and see what happens when measured true instead of the angled cross section. Where's my scientific calculator?

 

Glad your finding some information. There really is no voodoo in porting and manifolds, just good science. If you get hung up on the cross sections I might be able to come up with an excel program to help.

 

so in short, are we saying that some basic port matching in someone's garage or barn if done right will wake things up a bit or should all head porting be done by an 'expert'?

I may be naïve but do believe on a lot of heads, some clean up work at home, can wake things up a little..

 

Oh for sure it will improve performance.
What these guys are stressing,is that major scale modifications can't just be done without quantifying research and a ton of trial and error.
Major surgery needs to be backed up with flow bench work to quantify it,but cleaning up and opening up an incredibly restrictive set of stockers (like a 289 Ford)or cleaning up extra sloppy factory machining like most of the valve bowls on BBC factory heads) is always a good thing.

The tech that Aero and Vick are delving into is the really meaty stuff that we all inevitably crave once we get a taste of the improvements from the more basic stuff.
I,unfortunately,don't have the technical experience to contribute anything that would be much help at this point,but I sure hope Aero keeps on posting,because I am learning a lot of very useful,real world information from him.
You Sir,are obviously earning your pay cheques to the fullest.!

Scott


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Boston,
You are correct, especially on vintage hardware that didn't perform well from the factory. Combine a good port match with a good valve/blending job and a decent unshroud and you are probably 80% of the way there. All true experts started out as hobbyists, and usually refer to themselves as such. The last 20% or so comes from things like combustion stability, burn rate, knock sensitivity and such, and yes that is out of the realm of a hobbyist ( and even most head "experts" ). Not in a lack of knowledge so much but a lack of resources to test and develop it. And that's ok, the 80% or so will keep a smile on many a rodders face. Now if you were working on newer heads.....there just isn't much to gain. The Oems are producing now for daily drivers what racing guys were dreaming of in the 60's.

 

Scott,
Thanks! Im just a hobbyist that gets to play with some really neat stuff on the companys dime. I will try to share whatever I can.
-Aaron

 

I have seen some real gains from porting at home, I do agree though that modern heads are great, I have Brodix Track 1's on my un-hamb friendly 302 (I bet you can guess what type of car it is in)

I think for building period correct motors, reworking original heads without going overboard can work well.

I know a lot of modern stuff like 904 Vortecs for SBC etc will likely outperform a lot of early SBC heads, due to technology advances that made them way better to start with

 

I too, have seen some big improvement in "seat of the pants" performance on 302 Fords, by following some basic stuff. Thanks to all who have posted here. I have picked up a lot to think about.

 

Well I hope all my calcs were correct on hydraulic diameter of 1.5x2 oval.
And here's how i did the transition to 1.75 pipe according to my optimum primary size.
It was sooo much easier to do it this way too. A little math will tell you how big to make the parts. You have complete control over cuts and angle cuts as well as clamping ability until the pipe end is rounded out.

Although is seems like a choke down from the port size its really not theoretically because of the angled cross section. Hopefully the Venturi of the cone speeds up the gasses and all is well.

The pipe that's in the manifold is a smashed to oval 2" pipe then angle cut.
Royal PITA , the kind that give you ass cramps

 

...

 

Here's how it fits the car.
Another thing about fabricating the transition is you can easily compound the angle cuts. This helps dodge the header bolts and gets the sweep to the back started.

 

Nice work Man!
That has GOT to open up the breathing on the exhaust side by eliminating that hard angle and the immediate kinks in the primaries.
I'm going to be swiping some of that tech for mine,guaranteed.

Scott


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Nice work!!

 

All, I'm mostly a lurker but when I saw this thread I thought I should jump in since I have quite a bit of experience with porting, esp sbf stuff. The OP did a great job keeping it simple and his advice was spot on. Lots of great advice on this thread. For porting I use the Makita geo600. I added a rheostat for a ceiling fan to the cord so I could slow it down. IMO this is the best die grinder setup for porting hands down.

Carbide bits are very important. I get all of my porting stuff from mondello(I went to his school years ago) mondello.com and they offer all kinds of great carbides. For beginners I recommend getting a couple double cut tree shaped burrs with rounded tips. I don't like the real short shanks, I usually use the 3 or 4 inch long ones.

A tip Joe taught me was to get a rubber umbrella valve seal, and slide it on to the shank of your carbide with the concave side facing your grinder. Then after get the burr secured into your grinder, slide the valve seal over the nut on the grinder. This saves you from the frustration of nicking up a machined part of the head with the nut.

Inside and outside dividers are ESSENTIAL IMO to porting with any kind of consistency.

When porting you must learn to look at a port, see the restrictions, and go for the biggest ones first. All ports have multiple restrictions(even aftermarket heads).
Without flow testing equipment always think SMALL. Bigger isn't always better.

Ok, My 2cents regarding the SBF head.
The bowl work shown in this thread has been spot on. Mondello sells a really awesome tool that allows precise scribing of a circle in the bowl area. Ill post a picture of how it works when I get time.
On Sbf intake ports, the big restriction is the throat, and then the pushrod pinch. Dont even bother to gasket match the intake ports if you aren't going to widen the pinch area.
The intake port short turn radius needs to be rolled back a bit to get a sbf head to flow very well. In my flow testing the air just moves too fast and cant make the turn. If the short turn is not laid back the port will stall at around .450 lift and start flowing worse above that.

On the exhaust I agree that the floor doesn't need lowered, but widening it does help, along with raising it.

I will try to post some pictures that show what I am talking about when I get some time.

 

Excellent!Thanks Brother,and please lay some more of that info on us.
Joe Mondello is most famously associated with Chrysler Hemi top fuel heads,but guess who did the 289 heads for Carrol Shelby's racing program?

Scott


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Powrshftr refferred me to this post because like the other guy who wanted to try and take a stab at porting his own heads to gain some torque on a budget, which is why this thread was originally created.

Like a lot of us I don't have a lot of coin and want to gather some additional gains without having to spend a large amoney of money to do so.Thanks to everyone for taking the time to post their input.

-Mark

 

Ok guys this a shot of the intake ports on 2 mopar heads one is a 906 and the other a 516. Yes Scott these are the ones I keep looking at.
The deal I have been thinking about stepping on my .030. keith black piston 383 mopar engine strictly for drag racing.
I have been looking at the floor of the intake ports and I think the floor in the 906 (the open chamber head) feels much better to say it has more of a transition into the valve seat than the 516 head (the closed chamber on) which seems to be very flat to the seat.
Not sure if you can tell in the picture.

I really want more compression and not against buying a cam.
I guess the question is do you think that we can make the 516 heads work with some help or do you think the 906 would be the one to concentrate on?

 

Wow,that looks to be a big difference.The second one doesn't seem to have much of a short turn radius,or maybe it has a nice gradual slope to the valve seat that you just can't see in the picture.
Is it just me,or is the port quite a bit wider on the first head?

I don't have a ton of experience on big Mopars, but it looks to me if you could combine some of the characteristics of both of those heads (the tight quench of one,the unshrouded valves of the other,the larger ports of one),you would have a real axle buster!

Scott


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I see what you mean and the second one the short side is the 70* (?) cut and then it just goes to the port.
I have been thinking about some charcoal and some cast rod.

 

I wish I could get my hands on em.....I totally understand what you're saying about feeling the port shape with your finger....let's you sorta "feel" and interpret where it needs attention.

Without a flow bench to test them step by step as we go,low buck hillbillies like us have to just do what we think is right,and learn from trial and error.

I once read that Bob Glidden never dyno'd any engines,he based all his tuning and porting on actually running the motor down the track.
I guess that's kinda what we all do,right?Change something on the motor,take it out,run it,and if it doesn't go faster,go back to the drawing board.

What do the hardcore Mopar guys say?
They should have a pretty solid recommendation.

Then you can start whittling on em,and get that motor back together in time for the Meltdown!

Scott


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Oh the engine is together this is going to be the upgrade.
I thinking about in the pits cam change try it and then cylinder heads.

 

If the new cam works better with your existing heads,when you put your new heads on its really gonna rip!

Scott


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That's pretty much exactly what I ran the last Meltdown Drags with:

-Used 150,000 mile 5.0 forged piston short block

-Craig's list X303 cam ($40!)

-cleaned and re-used stock lifters

-home ported C6 289 heads

-home ported Performer RPM intake

-650 Holley

- 1-5/8" long tube headers

This pile of cast off parts ran a [email protected] on a super-soft 1.95 60'.
With a hard launch it would have cranked off a high 12 second pass for sure.

Car weighs around 2900lbs without my 230lb ass in the seat.

I'd say that's pretty decent bang for the buck

Scott


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As a new hamb.er myself, I love posts like this very informative and useful! I just got a 50 pontiac and this is an amazing resource, in a month or two I've read what must be thousands of posts, and I've found more info here than anywhere on the web. So thank you! Thank all of you!!

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Thanks PontiacGuy!

There are a ton of really great,helpful guys on here who are willing to share their knowledge with anybody who asks,so don't be shy if you do have a question

I too learned in leaps and bounds as soon as I became a member.....I had always wanted to build a Model A coupe drag car,but I had no idea where to start.
Since joining the hamb I was able to tap into the vast knowledge of the membership to learn everything I ever wanted to know about building a traditional looking 60's style drag car from an A coupe,early Hemi engine parts selection and assembly,Hydro transmission selection and repair,and a bunch more stuff.

Heck,within a week on the HAMB,I had accumulated more good photos and solid knowledge of Ford's "twisted leaf" A/FX front suspension than my previous 20 year search had been able to dig up.Im not kidding!
I'm close enough to be able to mock up a prototype of my own soon

So welcome to the HAMB and enjoy every minute of it!

Scott


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Yea this is my first build, well of an older car, and ive wanted to build one since I was a little kid, these cars are truly a piece of American history of a better time, in my opinion lol. And the hamb is just amazing for information I stumbled across it by chance and can tell you ill be a hamber for life! Thanks again! Ill post pictures of my progress very soon! Currently installing air bags....motor and tranny coming soon! Im addicted! (; thanks to everyone who has shared their knowledge for the young pups like me to keep the dream alive!

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