318 head porting for the average joe

[1wild&crazyguy]

There are folks who would like to get started on porting heads themselves along with those who might be curious as to what this or that will yield 'cfm wise'.... This thread is for them.

So it go's without saying that most of the time when the question of.. ''can i port my own heads?'' comes up ..most responses are.. ''just smooth the angles in the bowl and call it good'' ...well, i will do just that and then some as the thread go's on, so stay tuned...

1st up is a regular old 675 casting 1.78/1.50 head that i flowed as cast 'intakes for now' and then with nothing but the ''smoothed/rounded angles approach'' so we can see what actual improvement there may be.

*I had numbers from another int port on this head, but to keep it real..i started fresh and flowed the actual port that im working on*
as cast cfm@lift
.100--46
.200--108.6
.300--158
.400--169
.500--171
.550--173
.600--175
-------176\/

[oldkimmer]

.......looks like a good start.........we may learn something yet,.................kim.........

[1wild&crazyguy]

Here are the smoothed numbers and pics to follow.

just blended/smoothed with very lil material removed half way to the bowls roof.
cfm@lift after blend/smooth of 'just off the seat' angles, no ssr work.
.100--59.8
.200--113.6
.300--163.4
.400--169.4
.500--174.9
.550--177.3
.600--178
-----\/179
these pics are during the ''smoothing'' ..lol..but yeah uh..just showing where to safely play, hope it helps somebody.

Tomorrow i will do only the short turn, then flow test again.

this ''smoothing'' only does so much, the real restriction is beyond the ugly angles, its the area *between roof/guide and top of short turn*

[Marcelo Dart BR]

Thanks man, this thread will help me for sure.
Post some pics of the tools you are using if possible.

I took my heads to a shop just for cleaning. I'll pick them on monday.

I have a question - I'll run the 2.02/1.60 valves that I already have. Should I cut the new seats before starting any porting or I can cut them later? My plan is to start polishing the chambers and then cut the seats, so I wont run the risk of scratch or damage them.

[Badart]

Dang those flow numbers are pretty sad. LOL. This thread will help so many guys that ask the question "Should I run my stock 318 heads". LOL Did you happen to CC them? Just curious. Why is there such a small increase in flow numbers from .300-.500, just the tiny runners?

Good to have you posting again.

[64physhy]

Subscribed. I might try to do my 302 heads one some day.

[Valvebounce]

Thanks for posting this thread dude.
Once it's finished, it should be made sticky. I for one have zero experience with head porting, and a pair of 675's that I'd like to try and improve. "as cast" there are some pretty ugly burrs that I'm sure I can clean up.

[dvs265ap6]

I have a lot of pics of my heads i did at home guys, no one told me how either. they are 360 heads but the principals are the same. they might help, not gospel people but will give you an idea. The comments are about what i did and these heads were on a 360 stroker and had 500 horsepower. some of a set of 318's i did for dad that made 370 horsepower. http://s893.photobucket.com/albums/a...rting%20heads/

[Cudafever]

Originally Posted by Badart

Dang those flow numbers are pretty sad. LOL. This thread will help so many guys that ask the question "Should I run my stock 318 heads". LOL Did you happen to CC them? Just curious. Why is there such a small increase in flow numbers from .300-.500, just the tiny runners?

Good to have you posting again.

Remember, all that Justin has done is clean the casting flaws out of the bowl area, Nothing else.

I thing that is a big improvment. aka the way the chry enginner, designed the port to look before the casting department messed with it!

[Badart]

Originally Posted by Cudafever

Remember, all that Justin has done is clean the casting flaws out of the bowl area, Nothing else.

I thing that is a big improvment. aka the way the chry enginner, designed the port to look before the casting department messed with it!

I was talking about the numbers before he touched them. Looking forward to see what Justin does with these.

[1wild&crazyguy]

yes, nothing other than smoothed angles/casting flash just above the seat and nothing else

For those who cant wait...lol...i have already done one intake port and exhaust port that flow over 210cfm int/145cfm exh cfm w/1.78 factory valves and valve job.
If you knock out the guide it picks up quite a bit, lay the turn and go to about a '90% of seat' bowl and it really jumps.
the exhaust is easy on these, they have a good floor and all you have to do is raise the roof/knock out the kinks in it and round/enlarge the bowl...and bam u shoot from 118/120cfm...to 145-150cfm w/ 1.50 valve
When im done working today I will continue on, but for now heres the exhaust pics as cast vs one I did 6 months ago that flows the 145 cfm 'stock 340 exh flow numbers w/1.60'

The worked port is rusty, sorry bout that...i did it 6 months ago and it sat outside....when i get home ill toss it in the blast cab and then post the new cleaner pics. this is just till then..

[Abodybomber]

Curious on the valve job-serdi or old school sioux ?

[Rockerdude]

Cool! I love to learn how to port my own heads. You make it look easy.

[rumblefish360]

Being that you mentioned the magic numbers on a few things.....

flow over 210cfm int/145cfm exh cfm w/1.78 factory valves and valve job.

145 cfm 'stock 340 exh flow numbers w/1.60'

u shoot from 118/120cfm...to 145-150cfm w/ 1.50 valve

And people wonder why I would rather invest in a 318 head on a 318 instead of a 360 head on a 318. Smaller valves, higher velocity, and flow numbers that equal the bigger port/valved head. Your numbers match a stock big valve 340/360 head, if not better than some.

This 318 head will out perform a 340/360 head, give snappier throttle response and mileage because the air is moving quicker to atomize the fuel for a better more complete burn for more power.

There is a point where the bigger head is better, but for most street and mild street strip 318 builds, stay with the 318 head. Purchase a few tools and learn how to do it.

When the time comes to really step up at the plate looking for some serious power, either be brave and cut away or head down to your local head porter for a "PRO" job that will make you shine.

[1wild&crazyguy]

Today i decided to do 'just the guide'. I shortened it's length where it starts to about a 1/2', then slimed it and pointed it to the port window, meanwhile the only other porting done was just smoothing the casting and angles just off the seat half way up the bowls roof s mentioned above ..'still as cast/stock short turn'.

Now here are the new numbers.
--cfm@lift--
.100--60
.200--120
.300--168.6
.400--170.3
.500--179.4
.550--181.3
.600--182.2
--\/---183.4

[fzmax]

Did you actually lose flow @ .400 or is that a typo?

[1wild&crazyguy]

Originally Posted by fzmax

Did you actually lose flow @ .400 or is that a typo?

good catch, i was fried yesterday and read the wrong line @ lift.

So here are the numbers for comparison
---stock as cast----smoothed bowl casting/angles-----guide slim/reshape
.100---46----------------------59.8----------------------------60
.200---108.6------------------113.6---------------------------120
.300---158--------------------163.4---------------------------168.6
.400---169--------------------169.4---------------------------170.3
.500---171.7------------------174.9---------------------------179.4
.550---173--------------------177.3---------------------------181.3
.600---175--------------------178-----------------------------182.2
------\/176--------------------179-----------------------------183.4

[Marcelo Dart BR]

Justin I need some clarifying since I don't know where to begin. I'll run the 2.02/1.60 valves that I already have. Should I cut the new seats before starting any porting or I can cut them later? My plan is to start polishing the chambers and then cut the seats, so I wont run the risk of scratch or damage them.

I ordered an electric grinder, some stones and a standard abrasives porting kit.

[1wild&crazyguy]

Originally Posted by Marcelo Dart BR

Justin I need some clarifying since I don't know where to begin. I'll run the 2.02/1.60 valves that I already have. Should I cut the new seats before starting any porting or I can cut them later? My plan is to start polishing the chambers and then cut the seats, so I wont run the risk of scratch or damage them.

I ordered an electric grinder, some stones and a standard abrasives porting kit.

Yes polish the chambers, cut the seats, then port.

Not even joking here, i use a harbor freight grinder and champion burs that I buy long and then cut the shanks down for what depth i need. I also have a speed control...but i just keep thumbing on and off with the switch.
I dont use cartridges on sand paper, I do it by hand with 80 grit and mainly on the exhaust side and to just check for surface consistency....otherwise i just finish with the bur.

Control the grinder, it's not gonna be nice if the bur bites digs in...and i have a couple L shaped shanks to prove it.lol

[1wild&crazyguy]

Originally Posted by Abodybomber

Curious on the valve job-serdi or old school sioux ?

What ever the factory did, these came of a 40 thousand mile running 318, i just glass beaded them.

With a nice performance valve job...the numbers could only go up.

This shows what u can do with bone stock parts from the factory.

[Marcelo Dart BR]

Nice! Do you think I'm ok with the stones and the cartridge rolls or I may buy a carbide bur?

[Cudafever]

Justin, good to here your HF grinder works good. i bought mine on sale.

It when in the trash it was such a P.O.S.

[MoparDaddy]

I can't wait to get this done on the 'Doba

[1wild&crazyguy]

Originally Posted by Marcelo Dart BR

Nice! Do you think I'm ok with the stones and the cartridge rolls or I may buy a carbide bur?

rolls i spect are good for smoothing the short turn, but i like a almond head bur for doing the far side bowl, between guide and walls, corners...etc.

Larger barrel head cutters/burs are good for wall/roof.

[1wild&crazyguy]

Originally Posted by Cudafever

Justin, good to here your HF grinder works good. i bought mine on sale.

It when in the trash it was such a P.O.S.

I have killed 3 so far, but i bought the warranty.. lol

if i go easy and not lean on them..they seem to last longer as well.
I want to get a makkita.

Tomorrow im off work...so I will do the short turn and test, then I will do more bowl work and test again....after that, the roof & pinch...and so on.