906 Porting Tips

-
JGC403

JGC403

Well-Known Member
Joined
Nov 22, 2010
Messages
1,046
Reaction score
48
Location
Baileyton, TN
This will be the first set of heads that I have ported. I am a little worried about taking away to much material or removing it in the wrong location. I was going to just clean them up for now, remove any casting flash and gasket match the intake port. I have read that I shouldn't touch the floor of the intake port and that I shouldn't gasket match the exhaust port, if this is done flow is usually reduced. I would appreciate any tips.

Or is there any machine shops around Reading, PA that can do a good job porting these?
 
If this is the very first set of heads that you've ever attempted to do any port work on I would sugest this. In stead of useing carbide cutting tools which cut very fast get yourself some stones. They do not cut fast at all and they make a bigger mess, but after a few hours you will get the feel of it and then you can switch to the cutters.
Demon seed is right. Get the porting templates. If you use them you'll wind up with a decent set of heads. They are very easy to use and there are many peopel who have used them with good results.
Do you intend to install oversize valves?

Ted
 
some should have the link to wilds 906 head shop thread... he was going from 0 to fill tilt in a thread
 
thanks for the help. I'll need to order a set of those templates. Do the templates improve lift throughout the entire valve lift range or more at higher lifts?

The heads had a 3 angle valve job done and new seats installed several years ago. They have been sitting since, now I am getting around to using them.
 
I did up a set for the 1st. time, They still had the stock sized valves & flowed 268/198, Having said that, don't exspenct this to be easy, You need a steady hand & alot of patiants, A good size compressor, an inside mic., a few good bits & sanding rolls & a control speed air tool, The templets are fine as a "guide" but you'll need to go way past them for decent #s. To make the job much easier i'd just have them cut for the larger valves, this will take alot of the material out for you, just let the machinest know what your wanting to do & he can go deeper (in the bowl) with the cutter, here are other key areas for best results, just be "VERY" careful between the exhaust ports, thats where the water jackets are, If you don't feel like you want to tackle this, just invest in some aluminums & be done, exspect to invest a good 22-25 hrs. in them, Yes that much time.

Intake runners: Take the "pushrod pinch" area back .100", work on the roof some, you can raise the front roof "entrance" about .050", go back about 3/4", "DO NOT" touch the floors.
Take down the guide boss & the hump that goes in the runner, tailer this down & "tulip" shape or "teardrop".
On the floor of the intake port just before it enters the pocket is the "short turn", with the head flipped over as your looking into the pocket it'll face up, you will feel a small lip (ramp) running from side too side, you need to be "very" careful here, all your wanting to do is smooth down this hump but still keep the shape of the turn (no flat spots), use a lower cutting speed, don't go crazy here.

Exhaust: "DO NOT" gasket match the port, on the roof there is a ramp just inside the exit, tailer this down, I took about .070/.080" down, remember, flip the head over (chambers) faceing up, you will see the hump (ramp) just inside the exit. Theres water in this area too so be careful.

Exhaust pocket: Work on & tailer "tulip" down the guide boss as you did on the intake bosses, but there not near as hard to do, Other then these 2 areas just go past the templets some & stop, smooth the pocket & exit runner (whole thing). Smooth out with sandings rolls, "do not" polish the intake ports or bowl area. But you can polish the whole exhaust area if you want.

"Definitly" get a good valve job (3 angle) & get a 30* backcut on the valves, this alone is worth a good 8-10 CFM, If you really spend the time, I'm sure you can get 280/200 with the larger valves.

I would however get a junk 906 head & have at it, this way you know your limits, measure your depths.

Now that i've said all this here is the depressing part :D, after all this hard work, these heads still have a bad runner, even though they may flow the same as another head, the port effiency still sucks, so the other heads will give your better ET & MPH.

My "honest" opinion after doing this, I'd never do it again, just freshen up the heads & invest as little as possible to clean them up, drop em on, get the compression to a "true" 9.6.1 or there abouts, good size cam/matching springs, SD intake, 750/850dp, adj. valtrain, good ignition, converter/gears & have a blast.
 
So where are the tips from the guys who can get 320+ cfm from these dogs?
 
IQ52 said:
So where are the tips from the guys who can get 320+ cfm from these dogs?
Click to expand...

I don't think 320 is truely doable, 300/305 yes, but they are paper thin, plus like i said, any other head flowing these #s "for instance" the Indy EZs will blow them out of the water.

Theres only so much that can be done to these heads but in the end the port design still is what it is, I just did the basics & a bit more to mine, while just a few great head porters know how to re-shape a port to flow a bit better while the adv. amature don't, you need access to a flow bench for this. Its not just the #s, its more then that, you have to look at the "whole" picture of "how" those #s are flowing, not just the Max #s that most seem to look at, low-mid #s are everybit as important, sometimes more. Its been a good 6yrs. sence i did mine, I did alot of re-search, article reading & asking other well known head porters for tips/pics. Anymore when it comes to asking questions about porting old iron heads when there is so much better avialable on the market today for great prices, its like trying to dig up fossels, its becoming more exstinct.
 
You get it don't you J.Rob!

The guys what can do it don't tell. It cost them such an exhaustive effort to learn they won't give it to anyone. In fact, if the engine is wounded while out of town, they won't take the heads to another shop for any kind of repairs, even a seat touchup, just in case someone who knew what they were looking at might see.

They are not paper thin, they have no welding or epoxy and will cost you over twice what a set of stock EZ heads will.

From the same flow bench a few weeks apart:


.............standard port Indy EZ..............Ported 906

lift"...............Intake cfm.......................Intake cfm

.100................66.....................................91
.200...............127...................................165
.300...............181...................................219
.400...............232...................................272
.500...............272...................................299
.600...............299...................................325
.700...............315...................................335
.800...............N/A....................................339

The advice given in the forums CAN be helpful. It does sometimes cause me to cringe, as some things, past on as true, are just old mechanic's tales.

I have no complaints in this thread, except as to the exact elevation of the mountain we are climbing.
 
Where is the line drawn?

When you have busted your butt for years to figure all this stuff out, how much do you give away for FREE.

Thanks guys. It has been amusing reading these forums and I've gotten a ton of laughs. BYE.
 
IQ52 said:
You get it don't you J.Rob!

The guys what can do it don't tell. It cost them such an exhaustive effort to learn they won't give it to anyone. In fact, if the engine is wounded while out of town, they won't take the heads to another shop for any kind of repairs, even a seat touchup, just in case someone who knew what they were looking at might see.

They are not paper thin, they have no welding or epoxy and will cost you over twice what a set of stock EZ heads will.

From the same flow bench a few weeks apart:


.............standard port Indy EZ..............Ported 906

lift"...............Intake cfm.......................Intake cfm

.100................66.....................................91
.200...............127...................................165
.300...............181...................................219
.400...............232...................................272
.500...............272...................................299
.600...............299...................................325
.700...............315...................................335
.800...............N/A....................................339

The advice given in the forums CAN be helpful. It does sometimes cause me to cringe, as some things, past on as true, are just old mechanic's tales.

I have no complaints in this thread, except as to the exact elevation of the mountain we are climbing.
Click to expand...

Friggin tease. You should send me those heads so I can digitize them--Not for FREE obviously. J.Rob
 
The best '452's I have ever ported went high 280's on a SF-1020. I love cast iron heads--they make more power than their aluminum counterparts everytime. J.Rob
 
BTW LaRoy, Dont come here and chit on people who dont have the experience or means to even come to the findings you have, it only makes u out to be a conceded azzhole.

I remember when a certain genius jumped my chit on the 906 head thread when i even mentioned 300 cfm number, like it was impossible to do....it turned out that now i realize it was more of an ego trip as to how could anyone but them get such numbers.

And to rest of you, consider you might not know squat about the potential of this or that.
Parroting will bite u in the azz, cause eventually somebody will call u on it.



Have some class...
 
Too bad you're so far......

I have a set of 452's that are almost finished, well one head is done and the other is almost finished.

This was an abandoned project a few years ago as I was wanting to go "stealth" with factory components at one point, now I am all over weight savings. I would have offered them to you for a guide so you could compare finished product to a work in progress.

I know I'll finish the heads some day and stick them on something
 
So I thought that all I was going to do was get the Mopar templates and port the heads with those. That it wasn't worth putting anymore money into a set of cast iron heads.
But I picked up a copy of Mopar Muscle mag. In it was the builds of Amsoil/ Mopar Muscle Engine Challenge. Laroy Engines in Idaho made 730 horsepower on a set of ported 906 heads on stroked 440 to 500c.i. Heads are claimed to flow 340cfm.
 
JGC403 said:
So I thought that all I was going to do was get the Mopar templates and port the heads with those. That it wasn't worth putting anymore money into a set of cast iron heads.
But I picked up a copy of Mopar Muscle mag. In it was the builds of Amsoil/ Mopar Muscle Engine Challenge. Laroy Engines in Idaho made 730 horsepower on a set of ported 906 heads on stroked 440 to 500c.i. Heads are claimed to flow 340cfm.
Click to expand...

That would be member IQ52 . I don't think I have ever seen a set of 906's go that hi , I would love to see those heads on a bench I know of in Burlington, Vt.

but that is an impressive HP number if the dyno used didn't have the calibration that a certian dyno favored by magazines in californisa used ...
 
JGC403 said:
So I thought that all I was going to do was get the Mopar templates and port the heads with those. That it wasn't worth putting anymore money into a set of cast iron heads.
But I picked up a copy of Mopar Muscle mag. In it was the builds of Amsoil/ Mopar Muscle Engine Challenge. Laroy Engines in Idaho made 730 horsepower on a set of ported 906 heads on stroked 440 to 500c.i. Heads are claimed to flow 340cfm.
Click to expand...

Read JoeDust451's post again, there is some useful information in there. Look at wildguy's posts & pictures in the small block section about porting the 318 head. Look at his bowl pictures, you want something like that. Follow their suggestions and you'll see some substantial flow improvements, perhaps 30-40 cfm.

If you want the flows of a Edelbrock RPM head, buy the RPM head. It's not worth porting the iron head unless you do it yourself or you just want or MUST use the factory iron head. Anyone who will port an iron head for cheap, must not have done enough of them to be sick of it, or probably doesn't know what they are doing.

The magazine doesn't really tell the story. It indicates the 500 was rebuilt after someone forgot to turn the water on to the engine prior to the dyno runs. Yep, sorta.

It was torn down and put back together with the salvaged and scrap parts left after the bar-b-que. After that it made 11 dyno runs all over 716.5 HP with wiped out rings, 15 warped valves and seats, overheated and softened valve springs. So soft that some valves were hitting the pistons at 7000 rpm. The engine leakdown percentages should have been between 2-4% and tested at 7, 10, 10, 10, 26, 30, 32 and 56% AFTER the runs.

Even so it STILL made 730 HP.

"Claimed" 340 cfm!
 
JohnRR said:
That would be member IQ52 . I don't think I have ever seen a set of 906's go that hi , I would love to see those heads on a bench I know of in Burlington, Vt.

but that is an impressive HP number if the dyno used didn't have the calibration that a certian dyno favored by magazines in californisa used ...
Click to expand...

If the California dyno is Westech's, I've run there as well as Comp Cam's Dyno. I think they are both a wee bit stingy.
 
JohnRR said:
That would be member IQ52 . I don't think I have ever seen a set of 906's go that hi , I would love to see those heads on a bench I know of in Burlington, Vt.

but that is an impressive HP number if the dyno used didn't have the calibration that a certian dyno favored by magazines in californisa used ...
Click to expand...


I agree 100% John.
 
You must log in or register to reply here.
-

Back
Top