318 head porting for the average joe

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MOPAROFFICIAL said:
302 head info.

They are very restrictive as cast and flow a considerable amount less than the 675, 920 etc..without modification.
The picture shows the shrouding and what a simple stone drop can do to help that.
2" nickle chrome stone cut 15 degree bottom, outer edge cut to 45 then 60 above to create a nice transition and not leave a ledge at the chamber wall. Start there if you want to make the most of this casting, followed by a nice 5 angle 75,60,45,30,15.
Doing that will bring the numbers up by 25 cfm! as well as shift the bigger flow to start earlier in the lift range.
Example
Stock cfm........deshroud and perf vj
.100-48...............50-typical closed chamber
.200-87...............106 +19
.300-131.............157 +26
.400-152.............173 +21
.500-166.............179 +13
.550 peak-175.......179

Add porting and you can see numbers jump another 25 cfm from .300 up with 200 by .400 and peaking 210-215cfm around .500-.550. They weren't intended for high lift drag/perf. They do what they do early and don't need much cam lift.

1st pic showing a 5 angle vj vs stock
View attachment 1715791384
2nd pic shows a 4 angle vj and was the initial test port for the stock vs vj/deshroud and port.
View attachment 1715791385
Click to expand...
what size valves you working with???
 
:thumbsup: nice thread, great information.
Did the original author die and become a legendary member ? lol
I know he was at least 120 years old. Pretty smart old duffer.
 
fishmens67 said:
:thumbsup: nice thread, great information.
Did the original author die and become a legendary member ? lol
I know he was at least 120 years old. Pretty smart old duffer.
Click to expand...
I still get hbd's.. on not my birthday.
121 now...:D..though after 20 years of laying carpet, playing drums in bands ,building motors, fixing my family's cars ..I feel about 121.5 yrs old
 
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I started this thread, so I'm adding this 302 info to it, starting with this video.


I will also post here pics and details how like this thread was orginally intended.
 
What's the most cfm has anyone gotten from their stock 318 heads ( from porting ) and adding larger valves ? 260cfm possible ?
 
Jadaharabi said:
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Pardon me while I whip this out.
I think the question is what's the max you have gotten out of a pair of 318 heads?
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I have not max ported a 318 head with a 1.88. With a 1.78 valve they kind of stop in the 215-220 cfm range.
I think 230-240cfm with a 1.88 is about it.
I did some 'not all out' 1.88 273 heads and they went around 225 cfm. They end up near 140-145cc and that's tiny for anything but a 273/318. I don't think they would be the best choice for 6500+ rpm and or more cid..but it depends on the parts and pieces I'd suppose.
You need so much volume to be able to 'refill' at that rpm
 
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I just did some very nice 1966 closed chamber heads for a Mopar-mate.

I thought the intake port is well designed and needed the 1.88 valve to get the flow?
He has a nice Mopar and just wants to run quicker on the track, lets see if he will beat 17.00 lol...

HNY from Limey John

Hi again, did you do YT-VID No.3 yet?
 
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polyjohn said:
I just did some very nice 1966 closed chamber heads for a Mopar-mate.

I thought the intake port is well designed and needed the 1.88 valve to get the flow?
He has a nice Mopar and just wants to run quicker on the track, lets see if he will beat 17.00 lol...

HNY from Limey John

Hi again, did you do YT-VID No.3 yet?
Click to expand...
Yes. It'll be up soon.
 
Hi Moparofficianado,

Once you have mastered the 302 head, we need some of your expertise on the most forgotten head of the 1960's please!

Yep the most underrated 318 engine of all time the POLY!

So bad it only got a crappy dual quad set-up, whereas the later 318 got the mighty dual barrel lol...

-Dual-Quad-Poly-Stroker-(4).jpg


DQ 318.jpg
 
Jadaharabi said:
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Great vidios.
Can you make the text stay on the screen longer. I get it half read and poof it's gone.
Click to expand...
Thanks.
I know. Memory was low, editing wouldn't save, had to buy an sd card..go back.. re edit.. added that and 2 other captions last min to provide some brain food...and didnt drag them to the appropriate duration in order to read them completely. I meant 'main st' and typed "main road" missed the the word 'is' before 'expected.' Yes there are a couple biff's..
I recommend you pause to read it.:D
 
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Jadaharabi said:
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I use a phone for internetting. If I hit pause I get a bar of script across the middle of the screen that blocks what I'm trying to read.
Click to expand...
That's when you touch the screen in between the forward back and pause or play button and those go away and show just the movie still.
 
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