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915 head porting

  
Mopar Muscle
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915 head porting

 
Garys69RR Garys69RR
User | Posts: 99 | Joined: 03/12
Posted: 10/10/12
02:16 PM

Does anyone have any ideas on the best way to improve airflow on a set of 915 heads? These already have 2.14 intake and 1.81 exhaust valves installed. Will the Mopar porting templates work well if I cut them a little oversize to match the bigger valves? I know IQ 52 can get the 906 heads to flow really well. And I believe the ports are the same on both heads. Jim, (or anyone) are you willing to give us a few secrets to making the 915 head flow better without breaking the bank? I have read all of the head porting articles in Mopar Muscle that I can find. And I do plan on following their guidelines. I'm already using some 906 heads that I home ported, and they work great! Well thanks every one for any help/pointers. Ok  Laugh  

jerryg7 jerryg7
New User | Posts: 37 | Joined: 08/08
Posted: 10/10/12
06:08 PM

Have you read the Popular Hot Rodding "Cylinder Head Porting - Head Porting Basics" Feb 2009 article by David Vizard, or read his porting book?  

Garys69RR Garys69RR
User | Posts: 99 | Joined: 03/12
Posted: 10/10/12
06:10 PM

No but will check it out  

IQ52 IQ52
Guru | Posts: 858 | Joined: 06/10
Posted: 10/10/12
06:33 PM

Treat the 915 like you would the 906. It will respond like the 906 up to a point, but it isn't as good as the 906 despite their similar appearance. You will get into water sooner on the 915.  

Garys69RR Garys69RR
User | Posts: 99 | Joined: 03/12
Posted: 10/10/12
06:46 PM

Ok thanks IQ 52, I suspected the 906 could be made to flow better since you use that head in alot of your HP builds. Is that because the open chamber has less shrouding effect on the valve? Or is there more to it?  

451Mopar 451Mopar
User | Posts: 220 | Joined: 07/10
Posted: 10/11/12
09:05 PM

I wish IQ52 would give up some of his porting secrets, it sounds like he has spent alot of time developing the stock heads.
If you have used the porting templates, there does not seem to be anything special about them.  Mostly enlarging the bowls below the valves.  

Garys69RR Garys69RR
User | Posts: 99 | Joined: 03/12
Posted: 10/19/12
06:06 AM

Well got the heads delivered yest, same time I left for Wy. So can't wait to check them out. These will go on a 451 after I do some bowl blending, enlarging. Also plan to open up the push rod pinch area. The 906 heads I ported for it are working great, but I want the benefits of the tight squish area on the 915 heads, as well as the larger valves. Any thoughts or advice, 451? Ok thanks  

pepsi1 pepsi1
User | Posts: 150 | Joined: 10/11
Posted: 10/19/12
06:33 AM

Icon Quote451Mopar:
I wish IQ52 would give up some of his porting secrets, it sounds like he has spent alot of time developing the stock heads.
If you have used the porting templates, there does not seem to be anything special about them.  Mostly enlarging the bowls below the valves.


If everyone gave up a secret then, noone would have a secret:
  I'm sure you understand that when head porters find a place to make more Flow=Power we don't let everyone know. There are countless hours that go into cylinder head porting that we spent eating cast iron dust, valve angles also have alot to do with how a head flows. There I gave you a secret...LOL...
  Vizard has good books on head porting.  Grin  Cool  

IQ52 IQ52
Guru | Posts: 858 | Joined: 06/10
Posted: 10/19/12
08:31 AM

Icon Quote451Mopar:
I wish IQ52 would give up some of his porting secrets, it sounds like he has spent alot of time developing the stock heads.
If you have used the porting templates, there does not seem to be anything special about them.  Mostly enlarging the bowls below the valves.


Icon Quotepepsi1:
If everyone gave up a secret then, noone would have a secret:
  I'm sure you understand that when head porters find a place to make more Flow=Power we don't let everyone know. There are countless hours that go into cylinder head porting that we spent eating cast iron dust, valve angles also have alot to do with how a head flows. There I gave you a secret...LOL...
  Vizard has good books on head porting.  Grin  Cool


Thank you.  

Garys69RR Garys69RR
User | Posts: 99 | Joined: 03/12
Posted: 10/19/12
09:07 AM

Yes I agree with you guys, just thought I would ask. Lol. Hours of grinding, as well as trial and error testing. (Most of my trials are errors) Ha Ha. But thru the years I have gotten some great results by trying different approaches. One thing I have learned is that much of the improvements are made within 1/2 inch of the valve seat. Ok the secrets out!  

wyrmrider wyrmrider
New User | Posts: 5 | Joined: 01/13
Posted: 01/11/13
12:35 PM

That's the secret
I have a set of 67 915's stock HD  motorhome valves, ported by the late Kay Sissel
My setup is TRW "6 Pack" (heavy old school) pistons with a "turbo" D Cup of about 115 CC
block is decked with pistons +.010 out giving about .030 qench
(this block was seriously out of square and had large chamfers)
Cam is 256 @ .006, 204 @.050  .305 cam lift on the intake, slightly longer exhaust with same lift- Intake is max for a .904 hyd lifter at that duration
Isky 6006 dual springs
FYI seat timing is shorter than a lazy stock 440 cam, .050 about the same, lift about what a Magnum cam is
In a real heavy motorhome I run same intake lobe on exhaust for less overlap
I've also run 1.75 Sig Erson rockers on the intake only
In a motorhome motor do not radically profile the guides in the bowls
guides are thinwall bronze, knurled for oil retention, reamed and honed
Viton seals- always
valve stems are OD honed for oil retention and to catch the all to common not straight ones
TQ carb and C body CHP magnum exhaust manifolds
In a motorhome, street, mild cam I also just cut the intake seats to 30 degrees when installing the larger valves, open the throats with the Serdi.
Today much lighter pistons are available including the KB reverse deflectors
( which are modeled after this setup)
Edelbrock heads can replace the 915's but valve work needs to be double checked (clearance etc)
The KB "pop up in combustion chamber" pistons take some assembly work but are best for open chamber heads