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cam for swirl port heads

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Old Feb 24, 2008 | 09:00 PM
  #1  
Jonathan Dyer's Avatar
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From: Montreal, Canada
Car: '83 Berlinetta
Engine: 383 CI
Transmission: T56
Axle/Gears: 3.73, Eibachs, Tokiko Illuminas,
cam for swirl port heads

Hello, I had to change my water pump so I'm changing my timing chain as well. Now I'm wondering about maybe a cam and lifters while I'm at it. The car is a 350 with a regular Perfomer intake, manual 5 speed and 3.73 posi.

This setup produces a fair bit of low end torque, so much so that I could stand to lose some to a higher duration cam. I'm not looking to extend the rpm range as much as increase the power output in the 3500-4500 rpm range. That being said I don't want to lose too much at the bottom end. Should I leave it alone until I can do the heads as well or is there a cam I can use as a stop gap until then.

Also, a friend of mine put the RPM "Power Package" (intake, heads, cam) in has second gen 350 last summer and hasn't stopped grinning since (heavy agressive sounding lope, etc.). I've read alot of posts about how this is a somewhat outdated setup etc.etc. But from his point of view it was "easy" in that he didn't have to understand the numbers to match things up. I've never driven his street only car. Has he given up alot of what gets the car off the line in exchange for top end power that he'll not use?

Thanks
----------
oops, I should have mentioned that the car is carbureted (holley 650) and that the engine is a 350 from a 1991 c1500 pickup - highdraulic flat tappet with swirl port heads.
Thanks

Last edited by Jonathan Dyer; Feb 24, 2008 at 09:02 PM. Reason: Automerged Doublepost
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Old Feb 24, 2008 | 09:45 PM
  #2  
Sonix's Avatar
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
Re: cam for swirl port heads

What cam is in it now?

Pick a cam to COMPLIMENT the rest of the setup, not fight it.
Look at a compxe262HE, that would work GREAT in your setup, IMHO.
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Old Feb 25, 2008 | 11:21 PM
  #3  
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From: CT
Car: 92 trans am clone
Engine: LO3
Transmission: 700r4
Re: cam for swirl port heads

i really dont see a carb mixing well with swirl ports. why have great induction with horrible heads. not to start and arguement but ive seen it first hand and theyre just so flawed.
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Old Feb 26, 2008 | 11:14 AM
  #4  
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From: MA
Car: 93 GM300 platforms
Engine: LO3, LO5
Transmission: MD8 x2
Re: cam for swirl port heads

Lo-tec used a Cadillac junkyard 350 (using stock unported swirl port heads) and added a 214/220 deg Crane cam, a carb, a Performer carb manifold, and cheapo shorty headers. He ran 13.6 @ 101.5 mph in the quarter mile. Lo-tec's post

So the carb may not "mix well" with swirl ports, but they're good enough to run mid 13s in a 3rdgen.
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Old Feb 26, 2008 | 01:36 PM
  #5  
onfire's Avatar
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From: costa mesa/A.D. the largest Emirate
Car: 88 Formula 350
Engine: 5----->.7 or so they say
Transmission: seven hundred with a remainder of 4
Axle/Gears: 9 bolt 3.27
Re: cam for swirl port heads

Originally Posted by Sonix
What cam is in it now?
Pick a cam to COMPLIMENT the rest of the setup, not fight it.
Look at a compxe262HE, that would work GREAT in your setup, IMHO.
Don't try to get too crazy with your cam choice. It would help to know what kind of cam you have in there now and what are the specs on your head. Any additional information would be helpful.


Rabi C.
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Old Feb 26, 2008 | 09:39 PM
  #6  
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From: CT
Car: 92 trans am clone
Engine: LO3
Transmission: 700r4
Re: cam for swirl port heads

im not knocking the heads i wouldve loved to use them just why not match heads to induction? could make a great deal more power and pull higher rpms easily. but hey if it works more power to ya.
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Old Feb 27, 2008 | 12:52 PM
  #7  
Jonathan Dyer's Avatar
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From: Montreal, Canada
Car: '83 Berlinetta
Engine: 383 CI
Transmission: T56
Axle/Gears: 3.73, Eibachs, Tokiko Illuminas,
Re: cam for swirl port heads

Just a matter of $$$ and timing. Heads are in the future and I will look to match the cam with whatever heads I wind up with at the time. I'm just looking to get a bit more out of the engine for this summer while keeping the stock heads. Cam right now (I think) is:
Lift .382" Int
.402" Exh
Duration @ .050" 165.9° Int
174.8° Exh
Lobe Separation Angle 111.9°
----------
BTW The heads are 65.3cc chambers, 1.94"/1.50" valves, swirl port

Last edited by Jonathan Dyer; Feb 27, 2008 at 12:54 PM. Reason: Automerged Doublepost
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Old Feb 27, 2008 | 04:34 PM
  #8  
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From: Montreal, Canada
Car: '83 Berlinetta
Engine: 383 CI
Transmission: T56
Axle/Gears: 3.73, Eibachs, Tokiko Illuminas,
Re: cam for swirl port heads

Called compcams. They recomended the XE268H
Whereas they XE262 has a duration of 218 / 224 and
gros valve lift 0.462 / 0.469
The XE268H has a duration of 224 / 230 and
gros valve lift 0.477 / 0.480
LSA is the same at 110 for both.
Is there much of a difference?
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Old Feb 27, 2008 | 05:00 PM
  #9  
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From: PA
Car: 94 9c1 Caprice
Engine: LT1 (3-fity)
Transmission: 4L60E reBUILT
Axle/Gears: 3:08 POSI (out)
Re: cam for swirl port heads

The XE268H has to much lift for the stock Swerl Ports.
The 0.480 will hit the seals (seal to spring retainer).
That is unless someone has cut down the guide top.
But all is not lost, you can buy a set of .05 offset keepers,
if you want to use that cam.
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Old Feb 27, 2008 | 10:10 PM
  #10  
vipershark11's Avatar
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From: CT
Car: 92 trans am clone
Engine: LO3
Transmission: 700r4
Re: cam for swirl port heads

yea its the cam that makes those motors the dogs they are. plus put water in a swirl port head or port it and vacuum the shavings out pretty cool watching it all swirl out really fast.
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Old Feb 27, 2008 | 10:14 PM
  #11  
Jonathan Dyer's Avatar
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From: Montreal, Canada
Car: '83 Berlinetta
Engine: 383 CI
Transmission: T56
Axle/Gears: 3.73, Eibachs, Tokiko Illuminas,
Re: cam for swirl port heads

Thanks. That would have been useful info for the compcams guy to have given me!
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