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OEM SB 308 Head Flow #596555
01/28/10 03:01 PM 01/28/10 03:01 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
S
S/ST 3040 Offline OP
master
S/ST 3040  Offline OP
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S

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Posts: 4,595
On the south side of Nowhere
I've been looking at these things on the shelf for a while,
wondering what they would flow straight off an engine.
OEM valve job with .100" wide seat. I touched up the 45º
on both valves, just enough to clean them.

.................. IN .................................... EX

.100"_______54.0______________________51.8
.200"______108.3______________________99.7
.300"______163.6_____________________135.5
.400"______194.9_____________________152.3
.500"______207.9_____________________157.2
.550"______207.9_____________________157.2
.600"______B/UP______________________*****

***** guide prevented further lift

Intake port backs up above .550" lift.
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596556
01/28/10 03:04 PM 01/28/10 03:04 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
master
S/ST 3040  Offline OP
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S

Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
OEM 1.88" and 1.60" valves
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596557
01/28/10 03:12 PM 01/28/10 03:12 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
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S/ST 3040  Offline OP
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On the south side of Nowhere
Tulip valve required between 24.5º and 25º back cut to blend into back angle.

Results of using this valve with no other modifications.

.100"_______61.4
.200"______122.6
.300"______173.4
.400"______196.8
.500"______196.8
.550"______196.8
.600"______196.8
.650"______196.8

Again, I ran out of travel but, obviously saturated.

I guess "stalled" is a better term since, it can flow more than 196.8

Last edited by S/ST 3040; 01/28/10 05:42 PM.
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596558
01/28/10 03:16 PM 01/28/10 03:16 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
master
S/ST 3040  Offline OP
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S

Joined: Jul 2006
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On the south side of Nowhere
Pushrod pinch is .750" wide.
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596559
01/28/10 03:19 PM 01/28/10 03:19 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
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S/ST 3040  Offline OP
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......because
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596560
01/28/10 03:24 PM 01/28/10 03:24 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
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S/ST 3040  Offline OP
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On the south side of Nowhere
OEM intake seat.
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596561
01/28/10 04:31 PM 01/28/10 04:31 PM
Joined: Sep 2004
Posts: 2,091
oberlin, Ohio
Rapid340 Offline
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oberlin, Ohio
The low lift flow went up by almost 14% with the back cut.

1971 Factory Appearing Duster 340 11.000 @ 122 mph
Re: OEM SB 308 Head Flow [Re: Rapid340] #596562
01/28/10 04:46 PM 01/28/10 04:46 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
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S/ST 3040  Offline OP
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On the south side of Nowhere
Anybody familiar with OEM valves may remember the
pronounced ridge on the back side.
Re: OEM SB 308 Head Flow [Re: Rapid340] #596563
01/28/10 04:47 PM 01/28/10 04:47 PM
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick Offline
I Live Here
patrick  Offline
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
your peak flow with the back cut is about what I would've expected OOTB, ~195...

1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
Re: OEM SB 308 Head Flow [Re: patrick] #596564
01/28/10 04:57 PM 01/28/10 04:57 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
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S/ST 3040  Offline OP
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Yeah, I'm not seeing anything special here.
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596565
01/28/10 05:01 PM 01/28/10 05:01 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
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S/ST 3040  Offline OP
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On the south side of Nowhere
They appear to be about as "Swirl" inducing as any 587-up LA head I've ever seen.
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596566
01/28/10 05:28 PM 01/28/10 05:28 PM
Joined: Aug 2003
Posts: 3,245
Between a rock & a hard place
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cudadoug Offline
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Now what's your plan? I'd be curious to know how many hours (=$$) it would take to get them to flow around 240-ish, or equal to a RHS/X or EQ Magnum head...
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596567
01/28/10 05:30 PM 01/28/10 05:30 PM
Joined: Feb 2004
Posts: 4,501
Gainesville,FL
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goldmember Offline
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Gainesville,FL
Quote:

......because

I was talking with Larry Meaux a couple of years ago(great guy) and he had quite a few that came without the pushrod hole machined for obvious reasons.
Re: OEM SB 308 Head Flow [Re: cudadoug] #596568
01/28/10 05:37 PM 01/28/10 05:37 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
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Joined: Jul 2006
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On the south side of Nowhere
Quote:

Now what's your plan? I'd be curious to know how many hours (=$$) it would take to get them to flow around 240-ish, or equal to a RHS/X or EQ Magnum head...



No plan, as of now.

I was just breaking up the day from my regular grinding duties.

240 CFM would be easy.
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596569
01/28/10 06:44 PM 01/28/10 06:44 PM
Joined: Sep 2004
Posts: 2,091
oberlin, Ohio
Rapid340 Offline
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Joined: Sep 2004
Posts: 2,091
oberlin, Ohio
Quote:

They appear to be about as "Swirl" inducing as any 587-up LA head I've ever seen.





The swirl is produced by the runner. (and the pronounced pushrod pinch). I have never seen anything unique about the 308 chamber either.

1971 Factory Appearing Duster 340 11.000 @ 122 mph
Re: OEM SB 308 Head Flow [Re: Rapid340] #596570
01/28/10 06:50 PM 01/28/10 06:50 PM
Joined: Sep 2004
Posts: 2,091
oberlin, Ohio
Rapid340 Offline
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Joined: Sep 2004
Posts: 2,091
oberlin, Ohio
Quote:


240 CFM would be easy.




I got 278 CFM out of the intake by starting with the MP template kit (no longer available) and adding some other extras like raising the roof. I'm sure Vic could produce a lot better low lift numbers than I but the pushrod pinch limits peak flow.

1971 Factory Appearing Duster 340 11.000 @ 122 mph
Re: OEM SB 308 Head Flow [Re: cudadoug] #596571
01/28/10 08:27 PM 01/28/10 08:27 PM
Joined: Jul 2005
Posts: 428
wappinger falls new york
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Jimi_Vignogna Offline
mopar
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Joined: Jul 2005
Posts: 428
wappinger falls new york
Quote:

Now what's your plan? I'd be curious to know how many hours (=$$) it would take to get them to flow around 240-ish, or equal to a RHS/X or EQ Magnum head...



i did a set of 1.88 intake valve heads for a 318 volare stocker and with out porting and cover up got them to flow 234 @ .450 , the best 308 s/s head i ever did was 272 cfm at .700

https://www.facebook.com/VignognaRacingEngines
Re: OEM SB 308 Head Flow [Re: S/ST 3040] #596572
01/28/10 10:52 PM 01/28/10 10:52 PM
Joined: Jan 2003
Posts: 1,634
Petersburg, Va
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Darrell Offline
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Petersburg, Va
Quote:

They appear to be about as "Swirl" inducing as any 587-up LA head I've ever seen.


But the exhause radius is so much better, I have a set on my 450 lift 318 with 8.2 CR and would love to try them on a higher CR 340 or 360.
Re: OEM SB 308 Head Flow [Re: Darrell] #596573
01/28/10 10:58 PM 01/28/10 10:58 PM
Joined: Mar 2005
Posts: 3,445
N.Wilkesboro,NC
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DusterKrazy Offline
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N.Wilkesboro,NC
The 308's are pre-magnum right? What years would I need to look for?
Re: OEM SB 308 Head Flow [Re: DusterKrazy] #596574
01/28/10 11:01 PM 01/28/10 11:01 PM
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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S/ST 3040 Offline OP
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Joined: Jul 2006
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Quote:

The 308's are pre-magnum right? What years would I need to look for?



Correct. 88-91 360 only.
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