Cylinder Heads 101

[JoeDust451]

Sounds good to me Bobby!

[7demon2]

i think the priceing would be O.K. if it is only used as a guideline. the results and how to's are what i'm looking for. i have never done anything with a mopar before and would like to see some real world builds w/ results. thanks BJR!

[318ute]

Bobby,
Thanks for the information, this kind of thread is just the reason I like to visit this forum.
I hope to put into practise some of what you have offered in this thread and from our off forum dialogue.

Regards,
Steve.

[Scarecrow]

"Absolutely Fantastic" BJR Ive Have Heard of this stuff Before,But it Still Amazing,"Yet Ive Seen 318s Run some Some Pretty Decent Times Over Here & Aussie low 12s & 11s with Using the Exact Oppisite to What youve Praticed?? 360 Heads on a 318 some with 1.88 Int,& Some with 2.02s "So I dont Know"?? there was a guy Running a Really worked up 273 with the 273 Heads fitted with 1.96 intakes in a 65 Cuda for the Pre 65 Class of circut Racing & was clocked at 160+mph down the Back of Conrod Straight at Bahurst Australia Absolutly Amazing,Mind You Pretty Exotic Machine Though Roller Cam Venolia Pistons etc, You Get The Picture."I Guess at the End of the Day The Engine is Just A Pump" So If you Pump it Hard It Go Hard! Im Just Blown Away that You Ran A 318 with such Huge Compression & Still Used such Small Valves I Wonder What it wouldve Done with the 1.88 Intake Valve Fitted?? Also I never like the 360 Heads with the way the floor Drops Away I think 318s Have a Better Port Shape on the Exhuasts Just Get Rid of the Ugly Hump in the Roof LOL Woops I see Water!! Anyway Great work BJR

[BJR Racing]

Scarecrow,
We use to do the same things that your talking about, but when we found this other info that worked better then we used it. The heads showed a 20-40 hp gain depending on the cam and compression used. We went from running low 12s with the 360 heads to running in the upper 11s with the 318 heads, then we ported the heads and changed the piston to what the forum has and the car ran in the low to mid 11s.



BJR Racing

[Scarecrow]

"Thats Awesome BJR" I know in your chart you show theres Not much Differents in the 587s with the 2.02 int Compared to the 915s with the 1.88 int,"But You dont Show Figures with the 2.02 Valve Fitted to the 915 Heads to see Just how much more they do flow compared to the 587s,"But Im sure you have Done So with your years of Expertise."Also just What is the Biggest Valves can you Fit into a 318 Head Before you run into Trouble"I was thinking maybe 1.94 or 1.96 on the intake & 1.60 exhaust??? or would 1.88 int Do just Find as Ive Aready Ported Some 318 Heads to the Mopar Perfomance Guide Lines??

[BJR Racing]

Scarecrow,
I have put 2.02s in the 318 heads but this doesn't leave much left in the head for reinforcement. That head flowed in the 245 range but would scare me to run on the street. The 587s and the 915 heads are very similar in design, and if you will look back that the port runner volume was with in 2 ccs or so. Also if you look back and look at the low lift flow #s that the 2.02 is considerably less than that of the 1.88 done the same way.
The problem with putting the bigger valves in the heads is the chamber shrouding and the cylinder shrouding, and that the valves may actually hit the cylinder walls at lift depending.


BJR Racing

[Scarecrow]

"Thanks BJR for your Time & Expertise on the Subject"Ive spent countless Hours on Clylinder head Porting of Differing Types,& I Just Wished I had A flow Bench at My Disposal,LOL"It Cost me $75 to $80 a Shot to use a Flow Bench. "But with the 318 I Was Going to Go with the 360 Heads,"But Im Convinced Now to Use the 318 Heads as they are smaller Chamber Anyway & Comp Ratio wouldnt Drop as it Would with the 360 Heads! Ive Done a Dummy Head were ive fully Ported it & Raised the Roof on Both Ports trying to Copy the,W2s, LOL,Im Yet to go back to the flow Bench! But Before i do i would like to try just the 1.88 inlet to see if that Helps & Leave one Standard & Compare the Two side by side??"I agree with you on the Edelbrocks compared to the Iron W2s I know what i would Rather Have!!

[scampgt440]

hey
im not too knowledgeable about this stuff,but couldent you mill aset of 360 heads and get your compression back.

[BJR Racing]

scampgt440, Yes this is true but you'll have to cut about .050 off just to get to the same size as the 318s stock chamber size. This will equal about 10 ccs but have the heads cced before you start milling to know for sure where your at in the heads.


BJR Racing

[6t8 Dart]

BJR, what is your thoughts on the 308 heads? I am planning on a decent 360 for my Dart. Block and crank are a '72 vintage, want 9.0-9.25 CR, and a cam about 1 step above a '68 340 stick cam. The tranny is an A-999, the rear is an 8 3/4 with 3.55 sure grip(489 case). I have heard that the 308 heads are very effecient and require only minor work to get them to flow well, while "Going to town" on these castings is a mistake. What would you recommend ? This engine will get proper machining done (including deck plating and balancing), but nothing too exotic that is only useful in such applications as drag or road racing.

[BJR Racing]

6t8 Dart,
The 308 heads have a small window opening because of the big hole for the pushrod, and a larger bowl area. The larger bowl area is where the flow comes from, but this is very misleading as the bigger the bowl gets the slower the velocity will get even though the head will flow more air with a larger bowl. This is the same thing that Indy cyl.heads had done with the 440-1s, with these heads on a 446 engine you would have to turn the engine up to 8000 rpms to make them work. The 308s don't really flow that much better than that of the older counterparts when done properly. For the street engine that your talking about I would just do a bowl cut with a 75R7 cutter and leave about .060 before the valve seat for a additional angle to be put in of your choice. I would square deck the block a minimum amount and deck the heads a minimum amount, then run the .022 gasket from mopar, this should give you your 9.0-9.25:1 compression ratio. Most blocks will take .015-.020 to clean them up just as the heads will, just this difference will increase your compression ratio about 1 point and as the 360s were 8.5:1 or so from the factory this should put you where you want.
Then I would use a .484 from mopar or equiviliant cam, this may not sound like much but the difference is in the duration @ .050, and if you want a mech. cam the use the mopar .528 or equiviliant from who ever. But keep your centerlines and duration @ .050 similar or the driveability will be lost.
How much converter will you be running? If your not going to a stall converter then the .528 is out. As this cam will need at least a 3000 stall. Then I would use the .484 cam profile with a stock converter as the duration at .050 is a good bit less and more compatiable with the lesser converter.
Hope this helps you in your decisions.



BJR Racing

[D-mailman]

Hey BJR, again excellent post. I have had better results with the .528 over the .484 cams. The .528 has 60 degrees of overlap and the .484 has 68 degrees. I always have better vacuum with the solid .528 than the .484 hyd cam. Everthing else being equal. My compression is on the low side @ 9.02 to 1. That .484 cam is too soft on the bottom. JMHO. Anyway ..keep up the great posts. Terry.

[trigger_andy]

Hello all,
Ok this is my first post here but this thread has realy got me interested. I have never ported a head and realy an not sure how to go about it.

BJR, you said this to 64Ragtop;
Mr.64, What you have asked about the smoothing and the gasket matching. First DON"T SMOOTH THE PORTS, leave them as rough as you can as this helps atomization and doesn't hurt flow. Actually super flow says it has no effect on flow, but smoothing the ports will cause the fuel to puddle and cling on the port walls on the intake side. Causing a rich condition in the engine. But gasket matching and doing a good bowl blending will pick up the air flow greatly and HP, this will give you 80-85% of a fully ported head when done properly with a good valve job. So yes it's well worth it.

Can you or anyone for that matter please tell me, or post a link on how to carry out a mild port job to a set of 360 or 318 head's,please? Im in the same boat as 64ragtop. By the way I have a '69 right hand drive Barracuda and live in Scotland. Thanks.

[BJR Racing]

Trigger andy,
The main thing is to get the work done by a shop that can do performance, first and formost. If, and I mean IF YOUR DOING THIS YOUR SELF I can send you some shots,-pics. of how it should look. My E-mail is hotheadinc@hotmail.com or IM me here, and leave your e-mail address so to send pics.


BJR Racing

[moper]

Andy, What they are talking about is a thing called a "boundry layer". any material flowing donw a tube has friction from the sides of the tube. In a port's case, the material is air, carrying fuel in peices as small as molecules, and as large as visible drops. The fuel is heavier, and tends to want to "fall out" of the air stream. By leaving the rough surfaces, you create all kinds of tiny turbulence along the walls. These tiny eddies and stuff makes it harder for fuel drops to attach to the walls. Also, you reduce the surface area for heat transfer from the port wall to the mixture by a bit, which can also lead to fuel puddling at low engine speeds and larger overlap cams. Really, there is always a boundry layer of some size, and a rough surface vs smooth makes a very small difference in the thickness of the layer. On the exh side, smooth surfaces are harder for the carbon and stuff to attach to, so usually you want a nice smooth exh side. In intkae ports, I dont even touch the floor. The majority of the flow ina stock port is along the top and the shorter side wall (the "inside" port wall) until you get to about an inch upstream of the sort side radius into the bowl. If you've ever looked into a clean intake port, you can see the fuel stains where the air is moving slowly. The goal of a head porter is to keep the port as small as possible for the given engine, to keep the port stable and fast. Not to straighten every bend, and enlarge everything to the max.

[BJR Racing]

Well said moper!


BJR Racing

[D-mailman]

I second that BJR,..well said Moper...You are soo correct..Terry.

[trigger_andy]

Thanks for the post Moper. That has helped,cheers.

[rumblefish360]

The goal of a head porter is to keep the port as small as possible for the given engine, to keep the port stable and fast. Not to straighten every bend, and enlarge everything to the max.

And with that "Money quote" well said, it is amazing to me how offten someone will say the 2.02 - 1.60 360 heads made there stock 318 pull like a feight train as there only mod or with headers as the only other mod.
Balance in a package is were it's at!
Velocity is whats need. Even more so for the street.