Porting some Magnums for Sons 318LA

Seems like there has been a big influx of porting knowledge being displayed on the interwebs lately.
From Holdener doing some basic stuff FIRST TIME EVER and picking up good numbers to David Vizard getting on youtube.

I'm using an old article from Dulcich to do these.

Couple other guys Ive found on YT are Charles Sevedio, Eric Weingartner, Tom Mews (long winded) and also
Terry Grover (good listen on 1.5x speed lol).

Here's my attempt working on 2nd head exhaust first.

[video:youtube]wkoC6aqMeIQ[/video]

Son's engine specs so far:

Machine shop honed block, installed core plugs, ground crank 10/10, repaired/welded worn thrust surface on crank also.
Stock pistons flipped (even though it's been scientifically proven not to do squat) with new ring gap opened up.
218/218 summit cam bout .480 lift with 1.6 magnum rockers.
Magnum heads home brew porting under way.
Can't decide yet between Edelbrock LD4B dual plane or Holley street dominator single plane. Not sure which one I want to give up. LOL
72 904 with shift kit and tci 3000 stall convertor.
dual 2" exhaust/stock manifolds. Ooooof.

All going into 72 Satellite.

The car:

Great project.

I wish you well.

I own the original 1996 Mopar Performance clear plastic “porting templates” for the 1992-2001 5.2/5.9 V8 cylinder heads
and would be willing to attempt to take photos of them laying against engineering grid paper,
although my fuzzy memory is that already exists here somewhere in the archives of Moparts.

I worries me a little in the video that you keep using the word “smooth.”

Air moving through the Magnum intake ports is NOTHING like water flowing through pipes.

Swirl and Tumble intermixed with slinky like waves moving both forward and back
is a more productive way to try to imagine what needs improving.

The “soapdish” in the Magnum piston crown is all about creating “tumble”
and the flats outside the soapdish are all about creating a violent “squish” that boost a swirl
that started in the intake runner and was boosted more in the intake cylinder port.

The Magnum is a “fast burn” heart shaped head that gains power by needing less ignition advance.
Making flow “smooth” will reduce the fast burn power advantage, and can create a cylinder head that flows more but produces less hp at high rpm.

The flow out the exhaust port is nothing like water in a pipe,
a better picture to hold in your mind’s eye is the gas coming out a machine 9¥N.

Early Viper V12 engines used Magnum 5.9 V8 pistons for cost reasons according to Willem Weertman’s book,
which means that the ports and combustion chamber shape of the early V12 cylinder heads provide clues to getting high rpm performance gains when you modify the “truck engine” stock ports.

Porting templates

https://www.bigblockmopar.nl/tech/mopar-porting-templates-rb-la-magnum-heads/

A dozen years or so ago, I built a similar engine for my son's Scamp. Used the templates to port the Magnums. That engine ran great. First outings at the track netted 8.10s. I always wished I had put a little more converter and a little more cam in it. Mid to upper 7s would have been easy. And the thing idled and drove like a stock 318. What a great combo. Good luck with yours.

P.S. Get the templates. Don't shoot blind. Improvements are not necessarily intuitive.

The process is called porting but what us DIYers are really doing is removing casting lumps, chunks, burrs and flash. It is good to contour the valve guides (Not remove them as some back in the day advised.) No "hogging out" just making the port and bowl what the factory would have liked to have done but were refrained by cost. Many will say to just buy some new aluminum heads. If one has good used heads with healthy guides and seats than porting yourself is the best way for great power and on a true working mans budget. Plus its true hot rodding.

Thanks, Some good info.

I heard the templates were a waste of time:
the Mag article I'm using.
https://www.motortrend.com/how-to/mopp-0507-cylinder-head-porting/

Excerpt from Steve:

Critically analyzing our modification plan for the intake port, we started at the bowl area just under the valves, and we could see there were areas where large flow gains could be had. Blending the bowl and opening up the valve job to a spec closer to the full potential of the valve size will usually result in large flow gains. However, gains in these areas on the Magnum heads were modest. While there seemed to be plenty of flow left on the table in these areas, the bowls are proportionately large in comparison to the tight port runners. In contrast, opening up the pushrod constriction unlocked a substantial amount of flow, as did reworking the obstruction at the guide boss. It seems the Magnum's large bowl and small runner work together in kind of a happy harmony, with a balance of flow potential that requires mods at each end of the bowl and runner to significantly impact the overall port flow.

Article pics:

Not sure why it flipped em??

back in the 70's, when changing 318's to dual exhaust using the stock manifolds, we blew the pipes to 2 1/2" od as quick as we could for the full exhaust system, at the muffler shop.
made a noticeable difference in the was the car ran, plus better gas mileage ! [provided you kept your foot behaved]

Gonna keep it simple as possible.
Not many people like sniffing iron chips,

Man,

Those EAR HAIRS in your 50's coming on strong. hahahahaahah

I enjoy these types of builds and related posts. This is what hot rodding is all about-making the most of what you have. Looking forward to your impressions of the final results.

I realize it is too late but the effort and money in stock heads is exhausting when you can just get a set of Box Stock Eddy's and do a little clean up work to them

Haha,

I done spent way to much money on this boys FREE to him classic vehicles via early inheritance. (19yo kid, 73 Ford, 72 Satellite, LOTS of PARTS)

I'm retired and having fun on a "when I get the time" project I've been dreaming about doing since the early 2000s.

Yeah, I got a set of fully ported (300/209@6) Chinese Side Winders done up by Larry Smith for my project that have been sitting since 2017.
Billet 78/75 turbo in hand also.

Once I get this little 318 out of the way, it's GO time.

How on earth did you come to the conclusion that home porting the Magnums were a waste of time?

Dulcich says "Even with a basic effort, the exhaust flow improvement was dramatic, gaining a staggering 41percent." He goes on to say "The only question that remains is whether it was worth it. For the level of work involved and the power potential gained, we'd have to answer that with a resounding yes. Thirty-four cfm of intake flow has the potential to add a solid 50-60 hp to a combination built to take advantage of the additional flow, and we'd expect a nice extended power band with the increase in port cross-sectional area and substantial exhaust flow. With gains like that up for grabs, I'd spend a Saturday making cast-iron chips."

Are we reading the same article?

Cast iron heads take a good amount of time to port. I think that the instructions that accompanied the templates said something like 12 hours. And you will taste cast iron for days after that. But my experience mirrors Dulcich's. Definitely worth it!

I think you quoted the wrong guy. LOL

I stated using the porting templates was a waste of time.
Dulcich said that in another article on Big Block head porting me thinks, maybe even said that about the SB templates too.

Here is a snap of some txt Dulcich wrote on a board at least 15 ys ago
concerning porting templates.

I can't believe this was almost 24 years ago.

Wowsers.

I remember when these articles came out. Gulp.


https://www.motortrend.com/how-to/cylinder-heads/

https://www.motortrend.com/how-to/cylinder-heads-ii/

https://www.motortrend.com/how-to/cylinder-heads-iii/

2004

Magnum R/T head porting w/pics

https://www.motortrend.com/how-to/mopp-0407-magnum-rt-cylinder-heads/

For clarity:
Are these used factory production Magnum cylinder heads.
What casting number?
A guess as to year of vehicle they came off of?

They are not Magnum R/T heads, correct?

For a period the MP catalog listed ported Magnum heads for sale.
Perhaps someone here on Moparts would know who did the actual porting for MP ?
Mike Leach did Tri-Y Magnum tube headers, did his shop also do the ported Magnum cylinder heads?

I think one can state with confidence that these cylinder heads were designed with a top priority to reduce NOx pollution using the concept of Fast Burn.

But the cylinder head design was not enough alone for NOx.
EGR still had to be used from 40% throttle opening to 60%.
In those years, once past 60% throttle opening,
the “Rep. John Dingle Jr. Passing Power legal exception” kicked in
and emissions did not have to met at all.

My gut tells me to bet that
a MPI intake manifold combined with untouched R/T cylinder heads and cam
will out do any home porting job.

But if it is fun by all means do it.

These are early 90's magnum heads out of a Van.
They have the dual intake bolt hole patterns tapped from the factory.
I will never know how much power is picked up because there will be no baseline.

14.7 psi boost will double what ever gains are made, plenty for a 19 to 20 year old kid.
I'm sure after some time there will be project creep when his car gets spanked by dear old dads. LOL

Out of the box he'll say WoooooHooooo, this is waaaaay faster than the 390FE in the truck. (which he thinks is peppy now compared to his Echo)
Later he be like, Hmmmmmm

I have never seen any factory heads with dual drilled intake bolt holes. I think what you have there are either aftermarket castings or modified factory castings.

I agree 100% either someone drilled them or they are EQ heads (EQ heads of Odessa, Fl. - does both holes on magnum heads)

either way they are getting some more modifications from the sounds of it.

My fuzzy memory seems to whisper that EQ cylinder heads have larger ports than the factory Magnums and flow better, but not quite much as Mopar Performance sold R/T Magnum cylinder heads.

The early ones that are no longer made.

I remember way back when a member here made a jig he would loan out to drill the heads intake bolt pattern. Never seen or heard of a dual pattern from the factory.

These came off a van sitting in a junk yard back in early 2000s.
No way my memory gonna recall the specifics. lol
It looked 100% factory.
318 came with roller camshaft about 2 years before 360 started to get em.

Pretty sure I read on here a couple decades ago that during crossover the factory drilled the heads with both patterns.

NO.

the early magnum blocks were drilled for rocker shaft oiling, magnum head/gasket blocked it a deck surface. in 92-93 it was either a magnum or a pre-magnum LA head no duel bolt holes on mag heads. roller lifters were the crossover.

that's why someone made up a jig and started swapping on carb/intakes/t-covers hiding magnum roller cam engines in old mopars in the 90s and head rebuilders like Odessa head company in Odessa fl. started doing it to all magnum heads they rebuild and IIRC they cast the EQ heads new and machine them duel pattern. IIRC they do other head work custom order.

the early 92-93 5.2 blocks are best for LA head hybrid mix as they will oil the shaft rockers..

the early pre-magnum 5.2 roller lifters were not oil through and had a solid PRs, then they got oil through roller lifters with the solid PRs. 91-92 pre-mag LA 318 oil through roller lifters/w hollow PRs & through the shaft rockers. then they all swapped to the magnum head/blocks by 94.

any trucks with the 318TBI or a 360headed 4v 318 all got a roller block with a flat tappet cam/lifters.

correct 318 went roller cam in 85 with 360 in 89 with the #308 head (which are the good ones to find)

I remember the moparts rent a jig. seems it went MIA and never showed up again. late 90s

plenty of EQ heads went and still going out as replacements. JYs are full of them by now.

Roller lifters predate the magnums by several years, I doubt that's the crossover.

Nice Mopar Prochargerman!

We need more 71 Plymouths doing the 1320 lol...

Hopefully my 71 GTX will be back out after 20+ years doh...

I've been doing some small block porting too for my 64 truck.

But if I was gonna have a trick 71 it would be a 400 stroker methinks?

There is lots of info on heads and the all say ''don't go bigger than 90%' in the throat''...

But if you do the proper throat cut with a decent 'cutter' the the throat angle is already done for you...75 degrees or even 70 is OK!

The exhaust has a wonderful shape in the bowl area, so 'easy peasy'...

what I mean by crossover was on lifters. the non-oil through with the solid PRs then they got a oil through roller lifter with the solid PRs. then the last of the pre-magnum roller cam engines got oil through lifters & hollow PRs oiling up the PRs & up through the heads/rocker shafts.

next change was magnum head/pedestal rockers/oil-through roller lifters & hollow PRs - LA pre-mag & magnum share same oil through roller lifter but different length hollow PRs.

which is why I said you have to watch the roller lifter you use on a magnum engine as early non oiler roller lifters do not cross over to a magnum head engine.

and when looking building a LA/magnum hybrid, I have only found the early 92-93 magnum 5.2 to have block drilled for shaft mount rocker oiling.

also why I said most 90-91 pre-magnum 318s seem to have more of a VC leak issue/PCV-oil consumption issue as they oil both ways to the rockers and that is a lot of oil in VC area splashing around.

of course this is all just my opinion from what I have found working on them.

Mopar did a great job designing the magnum's exhaust port then did a piss poor job on the intake ports. You can grind the intakes some to get that pinch cut down. I ground an intake port on a 5302 magnum head and intensionally cut into the pushrod area to see how far is safe (see pics). I cut .129 (5/32") deep before I went through. So it looks like you can take 3/32" (.093) off the restriction and be safe.

I grind it out then patch with braze. Then find 8 bent pushrods (gets away from the port) works like a charm.

Haven't done the intakes yet on this head.
Just got back from "vacation" and will get back on them soon.