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Camshaft duration and lift for modified tpi

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Old May 30, 2012 | 05:14 PM
  #1  
L98IROCZ1987's Avatar
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From: Millersville Pa.
Car: 1987 IROC-Z Z28
Engine: L98
Transmission: T56
Axle/Gears: 3.70 9 bolt
Camshaft duration and lift for modified tpi

I am running an 87 irocz with a t-56 trans, 3.70 posi 9 bolt rear.
Im sticking with the tpi setup because I want it to look somewhat stock.
I currently have a 305 tpi 5 speed prom stage 2 by hypertech that I was running with 24 lbs injectors and a basically stock 355. I pulled the motor which has low miles to build it up a bit.i have ready a set ofheavily ported heads and stock intake manifold with slp runners.The heads are zz4 aluminum heads they have the stock valves and i gasket matched the intake and exhaust sides of the heads. I opened them up alot including the mounds around the valve guides and cut the guides even with the ports.My plan is to have the steel valve guides cut down so I can run a high lift cam with matching springs. I dont want to change the guides to or I would have to have the new valves cut.
The heads are 58 cc so I am not sure I want to run flat head or dish pistons as I was also thinking about running a 383 eagle crank this time. Not sure .. May run stock crank anyway im wondering if I can run a 5.25 ish lift cam and also any rec. durations?? Im am sticking with roller cam and 1.5 rockers . Also im going to run gear drive. I know that I am going to have a prom custom made / dyno so no big deal there. Thanks guys!
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Old May 30, 2012 | 06:32 PM
  #2  
vetteoz's Avatar
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From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: Camshaft duration and lift for modified tpi

Originally Posted by L98IROCZ1987
.The heads are zz4 aluminum heads
My plan is to have the steel valve guides cut down so I can run a high lift cam
Not required
ZZ4 heads come stock with springs good for .525 lift
LPE 219 cam ( .560 lift) works with them no problem

Originally Posted by L98IROCZ1987
I am not sure I want to run flat head or dish pistons as I was also thinking about running a 383 eagle crank.
So you need to all the calcs to see what CR you get with what piston on a 383 combo
What gas you want to run?

Originally Posted by L98IROCZ1987
im going to run gear drive.
EFI computers really love the noise / vibration from those
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Old May 30, 2012 | 07:03 PM
  #3  
articwhiteZ's Avatar
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From: Spokane WA
Car: 92 Lingenfelter Z28 articwhite
Engine: Aluminum 615BBC
Transmission: Th400wbrake/curri entps9" locker
Axle/Gears: 4.11/4.30/4.56
Re: Camshaft duration and lift for modified tpi

to run a gear drive ya have to have a chip cut. that will do away with the knock info

i run gear drives. mine retards 0.0
also good for Mech roller cams... just so ya know
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Old May 30, 2012 | 07:28 PM
  #4  
L98IROCZ1987's Avatar
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From: Millersville Pa.
Car: 1987 IROC-Z Z28
Engine: L98
Transmission: T56
Axle/Gears: 3.70 9 bolt
Re: Camshaft duration and lift for modified tpi

I have the l98 heads not zz4 , so it doesnt have the better valves ect.
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Old May 30, 2012 | 07:29 PM
  #5  
L98IROCZ1987's Avatar
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Joined: Aug 2010
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From: Millersville Pa.
Car: 1987 IROC-Z Z28
Engine: L98
Transmission: T56
Axle/Gears: 3.70 9 bolt
Re: Camshaft duration and lift for modified tpi

Ohh and I was going to run hyd. Roller lifters
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Old May 30, 2012 | 07:30 PM
  #6  
L98IROCZ1987's Avatar
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From: Millersville Pa.
Car: 1987 IROC-Z Z28
Engine: L98
Transmission: T56
Axle/Gears: 3.70 9 bolt
Re: Camshaft duration and lift for modified tpi

Pump 93 gas , ethonol bullshit and all
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Old May 30, 2012 | 07:46 PM
  #7  
vetteoz's Avatar
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From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: Camshaft duration and lift for modified tpi

Originally Posted by L98IROCZ1987
I have the l98 heads not zz4 , so it doesnt have the better valves ect.
You said ZZ4 heads

Alum L98 Vette "113" heads ARE ZZ4 heads, the ZZ4 have some better porting
http://ls1tech.com/forums/3412016-post9.html

http://ls1tech.com/forums/3335118-post8.html

Last edited by vetteoz; May 30, 2012 at 07:54 PM.
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Old May 30, 2012 | 07:50 PM
  #8  
L98IROCZ1987's Avatar
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Joined: Aug 2010
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From: Millersville Pa.
Car: 1987 IROC-Z Z28
Engine: L98
Transmission: T56
Axle/Gears: 3.70 9 bolt
Re: Camshaft duration and lift for modified tpi

Yep L98 - Right my mistake, so I am def replacing the springs. Do you know for sure if the guides will clear the cam you mentioned? I always thought the zz4's came with shortened bronze guides???
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Old May 30, 2012 | 09:08 PM
  #9  
L98IROCZ1987's Avatar
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Joined: Aug 2010
Posts: 68
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From: Millersville Pa.
Car: 1987 IROC-Z Z28
Engine: L98
Transmission: T56
Axle/Gears: 3.70 9 bolt
Re: Camshaft duration and lift for modified tpi

I found a camshaft similar to what the lpe 219 is.... Alot cheaper and a bit more agressive.
Its a comp cams xfi
249-sk08-464-8
Lift: 5.50/5.46 with 1.6 ***** im running 1.5*****
Duration - 252*/264*
Rpm range is 1000-5000 - seems good for a stock plenum like I am running rather then the super ram. Any opinion would be great ! Thanx fellow F body fiends lol
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