Originally posted by Ray Bell on the old forum: This is a Ben Simpson job...
Ben has plenty of heads, with a number of them being unusable due to extremely long periods out in the weather. One of these heads, which had had some valve stems rust right through to allow the heads to drop into the cylinders (!) he cut up and used to see what wall thicknesses there was in the ports and chamber... etc...
Here's the layout of the cut:
Ben has colour coded all this stuff... silver is head gasket face, black is combustion chamber (this with a valve totally rusted in, nothing on this head could be pulled apart, it was all so completely undismantleable that he cut it up from that point!), blue is water jacket, red is exhaust port and exhaust crossover tract (for manifold warming), yellow is inlet port.
Of note... the third picture is a horizontal cut showing the inlet port and exhaust crossover tract. After cutting, they sections have been laid out like opening a book. Note that there's a head bolt in the middle of that crossover tract... and that the bolt's still in there. I haven't yet asked ben, but there's a broken off bolt in the same spot on the block... sounds like he had fun getting that head off!
And the rest of the pertinent info from that thread follows: BY ABOMINATION Ray, have you or Benno ported a poly head before? Hell, has anyone ported a poly head before, or enough of them to have a "method" they follow, or a "rule of thumb"?
If so, feel free to color over the posted pics and show us what to watch for when porting, and where/how much to take off!
~Jason BY RAY BELL Ben hasn't started on them yet. At the moment he's doing another Holden engine for HQ racing, I think... and for the Dodge he's working on the panels while he awaits the right time to test all the blocks to see if there's one he can safely take out to 4" bores without offsetting them.
Believe me, when he gets serious there will be a lot of learning going on! His mate's flow bench will be working flat out for weeks, I suspect, only interrupted by the grinding of metal out of ports (and maybe the refilling of parts where they've been ground to see if the flow's better that way...).
BY ABOMINATION Gary had to get the following info from somewhere. Maybe he's ported a few?
Here's a blatent copy/paste from the 318 Poly Yahoo group, from Gary Pavlovich:
"The baseflow of a Poly head @ 28" water is as follows (all heads differ slightly in flow):
Bone stock un-cut Poly heads really perform "as is," however, the added cfm gained from porting is significant. I imagine that any good head porter can achieve these results (need a little more exhaust work here) but I have seen far less cfm gains from reputed "good" head porters as well as a little more flow; just depends. Head porting prices range from $550-1200+ depending on the person doing the work.
Yes, a Poly motor is capable of 500+HP with the right parts/machine work, although a 400HP Poly will blow-away wedge engines with much more "advertised" HP.
I smoked a "built" 360 Mopar Wedge engine with larger mechanical cam, more compression, Edelbrock aluminum heads, and better headers that ran on the dyno before my motor; our Poly made more peak HP/Torque at lower rpm and more average HP/Torque than the 360 wedge motor.
The 402" stroker Poly made the following peak #'s: 405HP @ 5600rpm and 442Torque @ 4400rpm (pay attention to the last sentence after all these HP/Torque numbers) and averaged over 400ft. lbs. torque to 5200rpm and still pulled 397HP @ 6000rpm;
From 3700rpm-4600rpm the average torque is 436ft.lbs.; from 4400rpm-6000rpm the average HP is 391;
and these numbers were all made WITHOUT TUNING, extremely lean 17 A/F ratio (air fuel ratio on the dyno), no cool air ducted into the motor or dyno room, and a severe exhaust restriction with #1 & #2 cylinder tubes feeding into one common collector that was collapsed in half; this is "the rest of the story" that I did not add to the Mopar Muscle articles I wrote in 2001.
A conservative estimate of HP/Torque for this single four barrel package w/the above problems corrected would yeild 435HP/450Torque in my opinion.
Poly 402 specs: Head flow as listed above, 290/.492" Hyd. cam (234@.050) 10.1 to 1 true compression ratio w/74cc chambers and JE pistons w/.927pin, 4" Mopar Performance crank Weiand #7503 single four intake (really crummy intake isn't it...?) and 650dbl. pumper Holley/850 TQ used, Ferrea 2.02/1.60" valves...
There's even a poly head conversion for B/RB/Hemi motors: www.nrcperformance.com/ (Those guys also have a sweet offset distributor).
No wonder folks want the poly head on their big blocks.
"A well-ported Poly head will increase approx. 30cfm on the intake side at .500" lift over a stock unported Poly head; worth the effort to port & polish these heads.
BY SCARECROW "Hey Jason Good work!! Thanks for the info, I Understand that this is What Gary Has Found,But as for NRC Making Poly Heads for the Big Block thats Stretching the Imagination a Bit isnt it Those NRCs while they are Good the Only common thing that they share is the Intake & Exhaust Ports are Seperated & They do have a Canted Valve set up But the Combustion Chamber is Nowwhere Near Polyspherical Shaped in fact its Pretty much Close Chamber or Near enough to it,Actually I Dont Like that Combustion Chamber Shape its To Much of a Heart Shape chamber for my Likeing Although they do show some Good Numbers on Flow Bench, But Flow Benches only Measure Flow through Ports & Valves at a Giving lift etc But they dont Really Tell us How will a Combustion chamber works & How it Effects the Combustion Stroke or Flame Front, The Hemi Shape Chamber is Still the Best Design in My Book & the Poly is The Next Best! Although Some Great Aguments can come from the Otherside of the Debate for those Supporting Wedge Heads & There Have Been Some Great Attcheivements Done with the Wedge Design But when they Start Covering the Quater in 4.3 Seconds then Ill Listen. "But I Just Hate the Way some of those Heart Shape Chamber Designs cut off the Exhaust side or Limit its Fuction of Design the Ability to flow After the Combustion Stroke & Out the Exhaust QUICKLY! As some of these Designs Flow Has to squeeze past two pionted Heart Shapes Just to go out the Exhaust Quickly & it is This I Dont Like One Bit! Remember if a Exhaust can Flow 75% of the Intake Charge then its a Good Head & Just Because the Ports Might Flow that,Does the Chamber Promote it!!??"There are Great Heads out there that are Great everywhere else then they go & Stuff it Up By Designing a Chamber that Hinders Flow at High RPMs,Even some of the Aftermarket Design Mopar Heads/V10 Viper Heads etc The Chamber isnt that Great in my Book, "Just My two cents"Anyway most of these Heads are Way to Expensive & Here we have a Poly Head that was Developed Like some Fifty years Ago to save on Production costs, But at the Same time Incorperate a Single Shaft Rocker setup with a Chamber design that still Offered a Great Design & Ports that were all seperated But still offered Good Flow Without the Exspense of a Hemi & the Deepest part of the Chamber was Right over where you want it over the Exhaust Valve with that Valve Sitting Flat & A Chamber that Promoted a Very Good Flow Charactoristics,Whoever Designed This Was a Genius & I Guess thats Why Chrysler Hired Him But Hes Probadly Long Dead Now So Will Never Know But He New Somthing of Chamber Design Thats Most of us Dont & are Still Learning,The Poly Head Design was Never Chased Hard enough Because Back then they Had the HEMI,But Whoever Design this Head Back then Must off Had the Ability to forsee the Future as Hemi was Dropped so this May have Been the Back up to Keep the Bean Counters Happy But Still Offer a Performance Basis, But then 1964 Came Along didnt it! Second Generation Hemi So the Poor Old Poly Never Really Got to See its Oportunity..Something to think about!!
BY RAY BELL That's very true, Scarecrow... the Poly never got a chance because the Hemi was there... and it lived in the USA, where no engine size limits applied.
It was only in the early sixties when NASCAR put a 7-litre limit on their racing that any question of not going bigger ever arose. And the 'small block' style of engine was neglected to a large extent because of that.
Then about 1966 they introduced Trans-Am racing on road circuits with a 5-litre limit, and by then the Poly had had its day. The LA was lighter too, so it got the development in that field and the Poly was left to power shopping car Plymouths, headers and farm trucks.
BY ABOMINATION It's a bummer. So close to greatness, yet so far...
Still, it seems that it may not be such a bad thing that the poly became the standard corporate engine that it did, powering grocery-getters, etc. It's because of that that many of the cars that did survive were those very ones, and being produced in large numbers, increases the chances of ending up with one of these motors in your "collector" car when you buy it.
And because all these people have 'em, then we have all the more people to rally around the poly, demanding reproduction parts, performance parts, etc. It's because there were so many of these motors that the parts aren't that hard to find (well, that and the parts shared with the LA) either.
I just wish that I could get the money together to reproduce factory-authorized poly aluminum intake reproductions (3x2, 4x2, single 4, log & tunnel ram). I have a foundry in mind, and the names of who I need to talk to about 'em to get the authorization to make 'em. I just need to get a few more intakes to sacrifice, and the cash for the molds & initial run. Pre-orders would follow, and then maybe a few runs (depending on whether or not these would be limited editions or not). I even have some partial pricing on most of this, but not quite enough to set prices yet (which I'd like to keep low, as the ones currently go for stupid amounts on eBay, and if I can price 'em so people could afford 'em, maybe more folks would run these motors).
Why haven't I done this? Simple - life happened. Married, kids, laid off, etc.
I'm a stay-at-home daddy nowadays and can't even afford a freakin' gasket set, let alone the cash to sink into a business venture that I can't be sure would even take off or could be sustained (I was planning on selling kits, stroker kits, cranks, done-up heads, headers, cams, etc on the side to supplement the income made by selling intakes in order to keep it sustainable).
So it sucks that I have to sit on all this for lack of venture capitol, but I'd be happy to consult if anyone else wants to enter into a venture such as this - hell, maybe I'd make calls, do PR, get magazine write-ups, features on TV, etc done in exchange for a portion of the profits and a partnership.
Until then, I'm stuck and can't complain about any lack of poly performance parts to anyone besides myself.
If I don't personally carry the parts, I can certainly talk several companies into picking them up.
If you're making them there, you may want to contact Craig Fountain at polymuscle318 at hotmail.com . He's the world's source of those new, reproduction finned aluminum valve covers, as well as several air cleaners, fuel logs, etc, and he's in Australia. Here's a recent reply I got from him:
Yes i do make other products. I make 4 different styles of air-cleaners which suit the 97-94 carbs you would use on a ploy tri-power, Multi carb finned fuel logs, and various other hot-rod components.
I have attatched a photo of a dressed poly which i have in one of my cars, and a full tri-power setup, with various scoops and fuel log sitting together, which are all components i make. There is a fourth scoop, which is a German Helmet with cast in spike on top.
I have these pictures, but it's late and I'm wanting to crash. I'll gladly email 'em to you if you hit me up. He's good people, he's VERY Poly-Friendly, and he does good work. Chat him up, Ray!
Post by DemonicDuster on Dec 23, 2015 14:33:26 GMT -6
anyone got a cutaway of the intake side. I would really really appreciate it. By the way, I'm new hear; as well as to the Poly world. I saw that S.A.M. entry in the vintage class at the engine masters well, now I'm hooked on building a Poly for my 87 D150, short bed, stock 4spd. I live in a big chebby area and, I want to spank a few unsuspecting fellars that don't shut up about how great their chebby is. Anyway I was just wondering about the intake side cutaway. I've looked around for some and, keep getting those fuzzy drawings that the factory put out years ago.