Porting Mopar 318 smog heads.

Mopardoctor · May 15, 2015

Home porting a set of Mopar 318 heads

This is my first shot of porting a set of Casting nr. 4027163 smog heads after the internet.
Have no flow bench, but it would be realy nice with some flow numbers after many hours of porting and surfing the internet with some of my own theorys about porting.

Gasket machting.

Standard metal gasket for 318 bolted over head and marked up.

Home made template for pushrod pinch.

Finished with gasket machting.

Here you can see the difference between old port vs. ported, and how far i dared to port
in mm.

67Dart273 · May 15, 2015

Sorry, I don't "receive" phacePlhant. No reason in the world, tho, that you can't lash up your own flow bench at least accurate enough for comparitive numbers. Google it. Basically it's a box to fit the chamber over, a variable speed control (lamp dimmer) on a shop vac, and pressure gauges, AKA manometers. And, a way of controlling and measuring valve openings

One I found on a quick search......

http://www.diyporting.com/flowbench.html

http://www.tonydrews.com/Flowbench/FlowBench.htm

"There's a forum" LOL

http://www.flowbenchtech.com/forum/

Mopardoctor · May 15, 2015

My org. bowl was 37,13 mm(1.46 inch), now it´s 39,30 mm(1.54 inch),
and made into trompet shape under valve seat to create a veturia effect
right under the valve.

Valve guide is cut 3 mm(0.118 inch)

The seats will be cut to 1.88 inch valve 3 angle.

Mopardoctor · May 15, 2015

67Dart273 said:
Sorry, I don't "receive" phacePlhant. No reason in the world, tho, that you can't lash up your own flow bench at least accurate enough for comparitive numbers. Google it. Basically it's a box to fit the chamber over, a variable speed control (lamp dimmer) on a shop vac, and pressure gauges, AKA manometers. And, a way of controlling and measuring valve openings

One I found on a quick search......

http://www.diyporting.com/flowbench.html

http://www.tonydrews.com/Flowbench/FlowBench.htm

"There's a forum" LOL

http://www.flowbenchtech.com/forum/

Would to realy like to bye the diyporting one, but not for now.

67Dart273 · May 15, 2015

LOL. Well the point is you can BUILD one that's fairly functional, and will at least give you gain / loss over "what you did last."

Mopardoctor · May 16, 2015

3 angle Valve job is hand cut with Neway 60/46/31 degrees.
Found a set of 1.88/1.6 inch vavles for 90 $ at Ebay, this will give me an intake bowl at 82.3%.
Intake bowl with 1.78 valve is at 86.9%.

Taking the sharp edge from 60 degrees and cutting again.

Finished the valve job, the 46 degrees is 2.5 mm now.

My stem height is now 47.94mm (1.887 inch).
The chrysler "bible" says 1.907-1.937 inch, the valves is sitting high in the chamber,
but read on the internet that they will settle with 0.02 inch after running the engine.
And the chamber is 67cc with 1.88/1.6, before with 1.78/1.5 valves it was 68cc.

496 polara · May 16, 2015

So when should I send you my 302's to play with........

Mopardoctor · May 16, 2015

496 polara said:
So when should I send you my 302's to play with........

I´m living in Denmark, that´s the reason why i´m doing these heads, a set of Edelbrock would set me back 2000 $ plus Danish tax and shipping.
But go a HEAD and port them, also look at 1wild&crazyguy 318 head porting for the average joe thread, which got me going.
And i don´t have a flowbench like him.

Mopardoctor · May 18, 2015

Exhaust cut at 46 degrees is 2.8 mm.

The exhaust bowl is now 33.15 mm (1.305 inch), also with a small trompett shape.
81.5% with 1.6 valve, 87% with 1.5 valve.

Thats how far i dared to go.

Gasket match for 1 5/8 headers.

xLURKxDOGx · May 18, 2015

Mopardoctor said:
Exhaust cut at 46 degrees is 2.8 mm.

The exhaust bowl is now 33.15 mm (1.305 inch), also with a small trompett shape.
81.5% with 1.6 valve, 87% with 1.5 valve.

Thats how far i dared to go.

Gasket match for 1 5/8 headers.

Nice work, makes me wish i had spent more time on mine and not rushed to put it back together just so it can sit there for another year

Mopardoctor · May 19, 2015

They are soon of to milling 1 mm (0.04 inch) on both intake and head.
These heads will be put together with Comp Cam 901-16 springs,
744-16 spring retaineers, 504-16 valve seals, and 604-16 valve locks.
Head gasket will be Mr. Gasket Head Gaskets 1121G 0.028 inch compressed, 6.177cc.
Cam choise is open, but think it will be Comp Cams XE 262 H with the org. 904 converter.

Mopardoctor · Sep 19, 2015

We went with 0.05 inch miling on heads, and 0.047 on intake.

Mopardoctor · Sep 19, 2015

The chambers is now at 56 cc volume with 1.88/1.6 valves.

Mopardoctor · Sep 19, 2015

Intake valves now have a 32 degrees backcut 0.8 mm wide (0.031 inch), the valves are from Enginetech.

RustyRatRod · Sep 19, 2015

When you say "smog head" you need to understand every single factory open chamber small block head is a "smog head". Even the coveted X heads. Same basic chamber and port design. The 318 open chamber heads mirror that, only in a smaller port version. Most any open chamber domestic V8 head is a "smog head". That was the whole purpose behind the open chambers. For better emissions.

Nice port work, btw.

Abodybomber · Sep 19, 2015

Nice work,indeed.. You took your time,and it paid off Congratulations.

496 polara · Sep 19, 2015

Look forward to seeing hp/tq numbers once it is finished.
What carb/intake/exhaust will you supply it with?

Mopardoctor · Sep 20, 2015

Will make a dyno on the wheels before and after with same cam(org. cam), just to see what gains there is with heads only, then i will put in a XE 262 H.
The exhaust is 3 inch dual delta flow 50, Headman Headers, intake Edelbrock Preformer, Holly 1850 600cfm.
Will port macht the intake to the heads, like oldmanmopar wrote about once, they can be as much as 1/8 inch off, and mark the intake up with the heads on the engine.
Will bye new pushrods from Comp Cams after blueprinting lenght (with 0.03-0.04 preload), this is made on a working man buggett, these heads now cost me 390$ with new valves and milling (gave 200$ for the heads in Denmark)

More will follow this thread in winter.

496 polara · Sep 20, 2015

The 3" exhaust is large for your setup and will likely cost you some torque but it should be a good runner regardless.

Mopardoctor · Sep 25, 2015

There is more pictures on my site in Denmark.
Thanks for all the attention and fine words.
http://www.bilgalleri.dk/fotoalbum/tuningprojekter/169913-portning_af_topstykker_

Bad Sport · Sep 25, 2015

Mopardoctor said:
There is more pictures on my site in Denmark.
Thanks for all the attention and fine words.
http://www.bilgalleri.dk/fotoalbum/tuningprojekter/169913-portning_af_topstykker_

I can't read that, lol.

Mopardoctor · Jun 18, 2016

My cylinder heads were just laying on the shelter, so i gave it a little valveseat cut on 15 degrees both intake and exhaust, and fine grade polish valve lapping.