LT1-LT4 Modifications 1993-97 Gen II Small Block V8

LT4 vs Z28 Springs

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Old Feb 17, 2009 | 10:19 AM
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Default LT4 vs Z28 Springs

Now I had a 69' and all the old guys would tell me to get Z28 springs, now is there a difference between the Z28 springs and the LT4 Springs because i have an extra set sitting and i want to put them in my 93'.
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Old Feb 17, 2009 | 10:22 AM
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Originally Posted by whytryz28
Now I had a 69' and all the old guys would tell me to get Z28 springs, now is there a difference between the Z28 springs and the LT4 Springs because i have an extra set sitting and i want to put them in my 93'.
LT4 springs have a little more seat pressure and are rated to a little higher lift than the stock springs (z28 springs you are referring to).
What mods are done to your '93? The stock springs will only work with the stock cam and 1.5 ratio rockers. If you add 1.6 rr's, use LT4 springs at a minimum. If you go with a larger cam or larger rockers, get some quality springs like CC 918's or PAC 1218's.
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Old Feb 17, 2009 | 12:48 PM
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Originally Posted by ss.slp.ls1
LT4 springs have a little more seat pressure and are rated to a little higher lift than the stock springs (z28 springs you are referring to).
What mods are done to your '93? The stock springs will only work with the stock cam and 1.5 ratio rockers. If you add 1.6 rr's, use LT4 springs at a minimum. If you go with a larger cam or larger rockers, get some quality springs like CC 918's or PAC 1218's.
The Z28 springs aren't reffered to the 4th gen z28.

These springs are .550 lift, more then the LT4 Springs. I think they came on the 70 LT1 motors if im not mistaken.
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Old Feb 17, 2009 | 12:51 PM
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Originally Posted by whytryz28
The Z28 springs aren't reffered to the 4th gen z28.

These springs are .550 lift, more then the LT4 Springs. I think they came on the 70 LT1 motors if im not mistaken.
70 LT1 motor?
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Old Feb 17, 2009 | 12:53 PM
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http://cgi.ebay.com/ebaymotors/HP-Z2...QQcmdZViewItem


Those are the springs that i have, and if they are crappy springs, then tell that to my 500hp sbc that daily drove me for 2 years.
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Old Feb 17, 2009 | 12:53 PM
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Originally Posted by ss.slp.ls1
70 LT1 motor?
Haha yeah the original LT1 engine was back in 1970. They came the corvettes and a few split bumper z28s i believe. They were solid roller engines which is why they came with .550 lift springs, which was HUGE back then. The average cam was around .480 lift.
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Old Feb 17, 2009 | 12:56 PM
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Originally Posted by whytryz28
http://cgi.ebay.com/ebaymotors/HP-Z2...QQcmdZViewItem


Those are the springs that i have, and if they are crappy springs, then tell that to my 500hp sbc that daily drove me for 2 years.
Well what are you trying to use them on? What mods?
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Old Feb 17, 2009 | 12:57 PM
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the old z28 springs were rated for a 500 lift cam...


first gen Lt1 style

i would not call them crappy but i will say out dated technology.. there are much better springs out there and to top it off those springs were not designed for roller cams

Last edited by 96lt1m6; Feb 17, 2009 at 01:02 PM.
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Old Feb 17, 2009 | 12:59 PM
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Trying to use them on my 93'.

Its got intake and catback now, but im doing cam, rr's the whole 9 yards. I wont be going over .550 lift because im using the LT4 hot cam (Freebie).

I just want to know if the LT1 heads will work with the Z28 springs. Size wise.
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Old Feb 17, 2009 | 01:00 PM
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Originally Posted by 96lt1m6
the old z28 springs were rated for a 500 lift cam...


first gen Lt1 style
Ok. Well i have the HP .550 lift version sittin in my garage.
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Old Feb 17, 2009 | 01:12 PM
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Originally Posted by whytryz28
Ok. Well i have the HP .550 lift version sittin in my garage.
yes,those were for the mechanical cam offered.
i still would not use them, the mechanical cam for those springs do not have the ramp speeds of a roller cam just for that reason i would opt for a newer style spring designed for roller applications.

too many times people say "springs rated for X lift " you really need the seat pressure and that really needs to be addressed. stock springs were 85 new,Lt4s are 100 and thats barely enough. 125-135 is really ideal
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Old Feb 17, 2009 | 01:15 PM
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Oh, didnt know that.
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Old Feb 17, 2009 | 01:17 PM
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I would get these:

http://www.compperformancegroupstore..._Code=LTValves

Or these:

http://www.pacracing.com/Beehive_Spr...Set_of_16.html
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Old Feb 17, 2009 | 04:37 PM
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There are also these: Don't know if the duals will fit the LT1 head, but i'm looking at the single spring rated @ 125 seat @ 1.80 installed height, 360 open pressure.

http://cgi.ebay.com/ebaymotors/NEW-1...4099QQtcZphoto

http://cgi.ebay.com/ebaymotors/SBC-C...4114QQtcZphoto

http://cgi.ebay.com/ebaymotors/SBC-C...0494QQtcZphoto
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Old Feb 17, 2009 | 05:58 PM
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Both good valve springs, but definitely from the "high rent" district. I put a set of LT-4 springs in my '96 Z-28 (the one with the "second generation" LT-1 engine) about 5 years ago, and they were only $70-75, from Scoggin Dickey. And, I think that included the retainers, IIRC.
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Old Feb 17, 2009 | 07:28 PM
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The original is actually written as LT-1, just like the original LS-6 which was a 454 Big Block in the 70s The new variations are not "Dash-number", so ours is actually just LT1 and the new LS is the LS6. I'm quite certain that GM did this to aid in differentiating between the old and new (GEN I and II). So if you have old, LT-1, 92+ is LT1

I'd stick with the LT4 springs for a roller motor, and also dual springs does not equal better. Single Beehives are pretty damn nice and I'd say are the most used in our motors.
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Old Feb 18, 2009 | 08:25 AM
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Originally Posted by Formula350
The original is actually written as LT-1, just like the original LS-6 which was a 454 Big Block in the 70s The new variations are not "Dash-number", so ours is actually just LT1 and the new LS is the LS6. I'm quite certain that GM did this to aid in differentiating between the old and new (GEN I and II). So if you have old, LT-1, 92+ is LT1
I suppose so, but I'm an "old timer", and grew up with the "dash" in the moniker. It's hard to learn new tricks. (my first "brand new car" had an LS-5)
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