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LT4 Hot cam

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Old Oct 11, 2008 | 03:43 AM
  #1  
Firebird sweden's Avatar
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From: sweden
Car: Firebid Cab-92/1989 TTA
Engine: 383 HSR TPI
Transmission: TH700r4
Axle/Gears: 4.10
LT4 Hot cam

Hi!
Does anyone now what springpressure recomended for the hotcam?
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Old Oct 11, 2008 | 11:18 AM
  #2  
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Something in the neighborhood of 110 seated, I believe.

Some outfits sell LT4 spring sets. Did you have a seller you were looking at?
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Old Oct 11, 2008 | 11:31 AM
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From: sweden
Car: Firebid Cab-92/1989 TTA
Engine: 383 HSR TPI
Transmission: TH700r4
Axle/Gears: 4.10
Re: LT4 Hot cam

Well i am using trickflow springs,trickflow sales told me that those springs would be fine for my cam,but they didn,t say anything about seatpressure and specs like that,dont wont to do another misstake.
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Old Oct 11, 2008 | 07:22 PM
  #4  
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From: Flowood,MS
Car: 87 IROC Z
Engine: 5.7 L98 TPI
Transmission: 700r4,2500 stall
Axle/Gears: G80,10 bolt 3.42's
Re: LT4 Hot cam

I thought that cam had like .525 lift which is at the top of what those springs will handle.
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Old Oct 11, 2008 | 09:30 PM
  #5  
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From: Saskatoon, SK, Canada
Car: '83 Z28, '07 Charger SRT8
Engine: 454ci, 6.1 Hemi
Transmission: TH350, A5
Axle/Gears: 2.73 posi, 3.06 posi
Re: LT4 Hot cam

Springs are cheap, and easy to swap if the heads aren't installed yet. Get the matching springs.

Most head mfg's use cheap s**t valve springs anyway, it would be smart to replace them right off the bat.
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Old Oct 12, 2008 | 01:22 AM
  #6  
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From: sweden
Car: Firebid Cab-92/1989 TTA
Engine: 383 HSR TPI
Transmission: TH700r4
Axle/Gears: 4.10
Re: LT4 Hot cam

I had a discusion whith trickflow tech and had the spec of my cam and say that the springs chould do fine,both lift and rpm 0-6000.

My old spring were only 90lbs and these are 140 so there is a big difference but still i do need to now the:

# Installed height
Coil Bind
# Open Pressure
Thanks
Anders
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Old Oct 12, 2008 | 01:27 AM
  #7  
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From: sweden
Car: Firebid Cab-92/1989 TTA
Engine: 383 HSR TPI
Transmission: TH700r4
Axle/Gears: 4.10
Re: LT4 Hot cam

Here is specs on the cam whith 1.6 rr.

24502586 Hydraulic Roller (LT4 Hot Cam)

The duration at lash point in degrees
(intake/exhaust) is 279/287; duration at .050" tappet lift
(intake/exhaust) is 218/228; and maximum lift with 1.6 rocker ratio
(intake/exhaust) is 525/525. Valve lash is zero/zero and lobe
centerline is 112 degrees.
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Old Oct 12, 2008 | 01:54 AM
  #8  
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From: Flowood,MS
Car: 87 IROC Z
Engine: 5.7 L98 TPI
Transmission: 700r4,2500 stall
Axle/Gears: G80,10 bolt 3.42's
Re: LT4 Hot cam

I`v heard that a few times before.Guy on the phone from a company tells me part A would work just fine with part B.Yeah they work fine after you get all the kinks worked out.And again they may be fine.I dont know those springs,I`ve just been throught that before.
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Old Oct 12, 2008 | 01:25 PM
  #9  
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From: Saskatoon, SK, Canada
Car: '83 Z28, '07 Charger SRT8
Engine: 454ci, 6.1 Hemi
Transmission: TH350, A5
Axle/Gears: 2.73 posi, 3.06 posi
Re: LT4 Hot cam

I still say swap the springs for the proper set for the cam. Springs are cheap, you can probably get the proper set for under $100, especially now that GM has discontinued the LT1 valve springs and made the LT4 springs the universal Gen II replacement valve springs.

If the heads are still uninstalled, then it will take you all of an hour to do both heads, and cost you less than $100, maybe a little more if you need to buy or rent a spring compressor.

Believe me, do this now, while its easy. I made this mistake with a set of heads I bought that had a "good" set of springs that would 'handle' .550 lift, which is lots for my cam that only had .490 lift. I changed all the springs out a week later because the valves floated at 5000rpm, with a cam that only really gets started at 2500 and is strong to over 6000.

It would be very much worth your time to do it now. Like I said, the mfg's use cheap springs just to sell them as assembled heads, they can't know what cam you'll use with their heads so they assume you'll change the springs to match anyway.
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Old Oct 12, 2008 | 11:41 PM
  #10  
Firebird sweden's Avatar
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From: sweden
Car: Firebid Cab-92/1989 TTA
Engine: 383 HSR TPI
Transmission: TH700r4
Axle/Gears: 4.10
Re: LT4 Hot cam

Ok
Here is what trickflow say.
And this is what i planned to install.

I would run the TFS-31400414 springs, TFS-31400424 retainers, TFS-31400434 Spring cups, TFS-31400444 Locks. That is good up to .600" lift.


Gregg Changet
Trick Flow Tech
E-mail: GChanget@trickflow.com
Ph# 330-630-1555 ext. 4694
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