915 HEADS
#230200
02/20/09 02:09 AM
02/20/09 02:09 AM
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Joined: Aug 2007
Posts: 475 HEMPSTEAD TX
CUUDAK
OP
mopar
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OP
mopar
Joined: Aug 2007
Posts: 475
HEMPSTEAD TX
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I have a fresh set of 1967 915 casting heads that i am concidering putting on my RB Cuda. These heads are fresh with 2.14 int. 1.88 exh. valves. uncut in stock condition otherwise. Many people have said that since the exhaust valve being cut to 1.88 that this will compromise the performance of these heads???? Can anyone help me with more info on the possible loss of performance?
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Re: 915 HEADS
[Re: CUUDAK]
#230206
02/20/09 12:43 PM
02/20/09 12:43 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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Since you have not run the heads on your setup before they were opened up you have no baseline to work from. there will be some gain but not near what could be had by either porting or a bowl hog cut with blending. The MP templates DO work very good(if carefully used) & they(the plastic sheet) would need to be cut .030 wider on each side & keep the same radius section when going to a .060 larger valve ie from 2.08 to a 2.14. I would do it if you could do it & not nick your fresh valve job & if not I would for sure unshroud the chambers on the front & rear sides of the valves.
live every 24 hour block of time like it's your last day on earth
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Re: 915 HEADS
[Re: RapidRobert]
#230208
02/20/09 02:50 PM
02/20/09 02:50 PM
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Joined: Aug 2006
Posts: 2,512 God's Country Maryland
GODSCOUNTRY340
master
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master
Joined: Aug 2006
Posts: 2,512
God's Country Maryland
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If you have larger valves installed and don't open up the pockets and bowls you just wasted your money. The stock pockets and bowls are too small for stock valves. 915 & 906 heads don't like 1.88 valves, they're too big for the ports and cause the flow to stall. They were used in max wedge heads because they had huge ports to compliment them. I've got ported 915 heads on our '72 Dart with 2.14/1.81 valves and it runs 10.38/ 130 mph, single four bbl.
I love the smell of Deer guts in the morning, it smells like... VICTORY!
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Re: 915 HEADS
[Re: GODSCOUNTRY340]
#230209
02/20/09 02:53 PM
02/20/09 02:53 PM
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Joined: Jan 2003
Posts: 75,017 U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,017
U.S.S.A.
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Quote:
If you have larger valves installed and don't open up the pockets and bowls you just wasted your money. The stock pockets and bowls are too small for stock valves. 915 & 906 heads don't like 1.88 valves, they're too big for the ports and cause the flow to stall. They were used in max wedge heads because they had huge ports to compliment them. I've got ported 915 heads on our '72 Dart with 2.14/1.81 valves and it runs 10.38/ 130 mph, single four bbl.
please stop clouding the issue with facts ....
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Re: 915 HEADS
[Re: CUUDAK]
#230214
02/20/09 04:05 PM
02/20/09 04:05 PM
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Joined: Jan 2003
Posts: 75,017 U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,017
U.S.S.A.
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Quote:
Quote:
There is a certain amount of porting that has to be done when you install larger valves , if you don't you will see no increase in performance .
What heads are currently on the engine ?
Also are you sure they are 1.88 ? I'm not sure there is enough room to get those 2 valves in that heads
Totally positive, A friend of mine had these heads done at HP PERFORMANCE here in Tomball, Tx. the tech that did the job told him that going with the larger exhaust valve would kill bottom end torque. I was a little skeptical so before i install them i wanted to ask first. I have stock 906 heads w/2.14 int & 1.81 exh valves and a Torker 2 w/850cfm Holley dp on a 1969 440-6 hp bottom end now. All original internals (6 pack forged crank & rods) except for the speedpro flat top pistons. Its no slouch by far but i am used to my high 8 second Falcon. It has been a while since i had a decent street car. The cam is an off the shelf Hyd Lunati and was told that lift was 604 int., this has not been confirmed. Definitely has a hefty lope and stops pulling around 6200 rpm. 4 speed w/ 3:91 sure-grip. I am looking for a solid 11:50 car that has good street manners. I did purchase a set of Snapon cutter bits to do a bowl blend and clean up the runners. Who has the Mopar templates?
Other than a small bump in compression you probably won't see much of a gain with the 915's .
Same goes for the at least ONE other heads should you mention should you decide to run them OUT OF THE BOX from what little I have paid attention to.
The templates are for stock valve sizes , if you aren't really sure what you are doing trying to adapt them UP might make the heads flow WORSE than stock in the mid lifts , I have a pair of 906's that the local, well versed, machine shop I use did their COMPETITION VALVE JOB on , cost me 250 bucks , the heads flowed WORSE than untouched heads when they were done
Last edited by Johnahah; 02/20/09 04:09 PM.
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