318 head porting for the average joe

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pishta said:
question: If the short side radius and valve blend is so easy to do , why did Mopar not cast this into the heads from day one? C'mon, you cant tell me in the HP race of the late 60's that Chrysler didnt see this garbage as low hanging fruit for an easy casting fix? Its funny to see basic porting add 50HP and not have it realized by Mopar. Do these porting steps kill real world street RPM torque?
Click to expand...
Easy? bowl blend yes, SSR well, if you say so. Personally, i would never recommend it to a beginner.
To answer you question. because the man that designed the head was Performance minded.............the man the made the final design on the casting was Cost minded.

I can just here the argument. "Performance: YOU CHANGED MY DESIGN AND DESTROYED THE HEAD! Cost: At .420 lift it don't flow any different and it cost less to make. Performance: YOU LOST 20 CFM!!!! Cost: like i said, didn't change a thing. And i will be the one that gets a bonus for saving the company money.
Corporate: nothing wrong with the engine SHIP!
 
Yeah, I guess your right, although making W2 heads must have been a colossal bust when they could only sell them to the race teams and not put them on a production truck, and the T/A head with its unique rockers and pushrod hole that still had the same port? They could get a new rocker arm designed and produced ($$$) as well as change a production step ($) but couldnt clean up a casting mold? Corporate Chrysler when a nickle was worth a million. ....There was an in-house Ford 4cyl head that was a Cosworth killer and the production run ended up having an intake port with a 90 bend in it, as opposed to the almost 45 straight shot it was designed with for hood clearance that wasnt on the initial plans. The designer quit!
 
Now that sound just about right.
They would have been so GREAT to have production W2 eng. but them W2 came out during the gas crunch. Everyone was looking for M.P.G. not HP. Would have been a hard sell on a 79 Cordoba......... I mean they were already tooled up. could have been easy to put into production.
 
After seeing the Engine Masters S/B stroker dyno runs with Edelbrocks, I think the iron heads are all but finished on strokers, doh...
So when I saw a set of Brodix B1-BA come up for sale in the UK I snapped them up!
Gonna fit some 1.60 titanium ex race valves in them and bolt on a Blower!!!
If Folks can run mid NINES in the UK with Eddy headed 408-360 motors then I feel the EIGHT's coming into view lol...
441cube S/B, (+100 360 with a Hughes 4.100 crank), maybe even sevens???:rofl:
 
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TI on the intake
TI on the exhaust drags only or do others have success on longevity
I tended to use Inconel on the exhausts on turbo IDK about Mopar LA and Blower
should not be too bad unless U have too much overlap
keep the valves on the seats to keep them cool if you want longevity or HD use
 
I hate to be simple. ur doing port ? udoing polish? you ask tell all of us. work on any head is not as by hand simple by hand. a good way is to have valve job done. company a good one. take heads any and u get some measuring stuf as in cooking. take this for chamber head.. valves closed heads level take and put or inject fluid into open chamber on head block side turned up and level measure. that's ccd.. do the same 4 intake port and exhaust port keep turning with valves in head. port and redo same to ck ur self.. . as good as any volume is what works. now smooth and flow cones second.
 
charles mill said:
I hate to be simple. ur doing port ? udoing polish? you ask tell all of us. work on any head is not as by hand simple by hand. a good way is to have valve job done. company a good one. take heads any and u get some measuring stuf as in cooking. take this for chamber head.. valves closed heads level take and put or inject fluid into open chamber on head block side turned up and level measure. that's ccd.. do the same 4 intake port and exhaust port keep turning with valves in head. port and redo same to ck ur self.. . as good as any volume is what works. now smooth and flow cones second.
Click to expand...
comes second not cones thanks.
 
thanks I did this yrs ago. hay I kicked *** and won. point simple new and any head this works. WORK YES. simple kinda.
 
Great thread, glad it helped some people.
Found a set of 920 closed chamber heads.They had hard seats, so why not..
Closed chambers. Ugly lookin edges and shrouding.

Flowed a intake on 4" bore @28"
.100-55
.200-109
.300-161.2
.400-177.9
.500174..turbulence
.550-177.2
.600-181





20200101_170551.jpg
 
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Cleaned up chamber a little, still right at 3.90" bore size. From the factory these heads are already bigger than the 273 bore.
Some people call the recess next to plug a depth point for the machine process...others say it's for the flame colonel. Food for thought..

Flowed after the chamber shape valve unshrouding, nothing else.note this head has a valve job , very basic, thin seat margin though lacking somewhat to the factory valve job top cut/lower.
Int cfm @28" 4" bore 1.78 valve
.100-59
.200-113
.300-165
.400-182
.500-178
.550-181
.600-181.5
.650-184




20200107_151610.jpg
 
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Worked and shortened the guide, straight/common wall, bowl, opened pinch and removed .030 from the roof half way in and right over the turn. What you call very ported....yet I did not gasket match the port window at all. Hand cleanup with 60 grit right in the bowl under the seat. Hope it helps somebody who wants to modify these heads low buck.
Intake Cfm @28 4" bore 1.78 valve
.100-62.9
.200-120
.300-172
.400-195
.500-201
.600-207
..beyond turbulence 193cfm
These rival stock 360 flow #s...but who cares.
20200111_135755.jpg


20200111_135002.jpg


20200111_134937.jpg


20200111_134727.jpg
 
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Thanks for the update
I'm going to try those heads with a slightly larger intake and 30 degree seat and see if I can get rid of that step just outside the current valve
I''ll cut the bottom steps, like 3 on the serdi and blend the bottom
whatta you think
 
Wyrmrider said:
Thanks for the update
I'm going to try those heads with a slightly larger intake and 30 degree seat and see if I can get rid of that step just outside the current valve
I''ll cut the bottom steps, like 3 on the serdi and blend the bottom
whatta you think
Click to expand...
Easier than hand shaping the entire thing.
Cut the seats, stones are great but the cutter is so consistent and clean. The bowl size needs maxed.
 
Wyrmrider said:
Thanks for the update
I'm going to try those heads with a slightly larger intake and 30 degree seat and see if I can get rid of that step just outside the current valve
I''ll cut the bottom steps, like 3 on the serdi and blend the bottom
whatta you think
Click to expand...
Are you really going to cut the seat and valve to 30 degrees or did you mean the top cut was going to be 30 degrees on the seat.
 
cut the valve and seat
works to give more "curtain area' for low lift grinds under .500 roughly
of course really high lift cams can go more than 45 degrees
It's also a way to get a new higher seat just sitting the valve on top of the old "top cut"
which it appears the head in question does not have much of
for the valve you have to start off with a larger one and cut it down or the edge gets too thin
I usually measure the curtain at the inside of the seat
others use the outside
 
MOPAROFFICIAL said:
Cleaned up chamber a little, still right at 3.90" bore size. From the factory these heads are already bigger than the 273 bore.
Some people call the recess next to plug a depth point for the machine process...others say it's for the flame colonel. Food for thought..

Flowed after the chamber shape valve unshrouding, nothing else.note this head has a valve job , very basic, thin seat margin though lacking somewhat to the factory valve job top cut/lower.
Int cfm @28" 4" bore 1.78 valve
.100-59
.200-113
.300-165
.400-182
.500-178
.550-181
.600-181.5
.650-184
Click to expand...

Interesting to note these heads are flowing 182 at .400 and no more after that. No wonder cams for 273's are in the low .400's. Just a waste of motion to go any higher with unported heads. Thanks for all your work!
 
66fs said:
Interesting to note these heads are flowing 182 at .400 and no more after that. No wonder cams for 273's are in the low .400's. Just a waste of motion to go any higher with unported heads. Thanks for all your work!
Click to expand...
No prob, neat stuff.
In stock form, definitely.
Many things considered.. like the intake manifold bolted on makes the hiccup go away as well as knocking down the numbers a touch...then you look at the factory cams, 340, 383 roadrunner cam, tnt .. all right at the fall off of the heads in question. Chrysler presumably designed that in with both series 273/318 and 340/360 heads. They all hiccup around .490 lift and then reemerge, some, by .550 lift.
The intake port above is probably around 132cc , tiny, but will make the little motors breathe fire without skipping a beat.
 
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MOPAROFFICIAL said:
The intake port above is probably around 132cc , tiny, but will make the little motors breathe fire without skipping a beat.
Click to expand...

From memory my 302's are about 136-140cc but with a 1.90 11/32 valve the flow is up to 242 cfm @ .500
 
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