JOHNNYMO

iTrader: (1)

So I was thinking with the 150k miles on my engine, it might be a good time to freshen up the valve springs. Car is a 93 Z28. I have no issues, but I want to also do the valve seals, so I figure why not new springs and keepers? Is it ok to run LT4 springs on the engine as it sits?
Thanks!

hrcslam

Is it stock? If so, you can, but there are better options.

JOHNNYMO

iTrader: (1)

Headers are in the works....MSD opti,coil 8mm wires, BBK UD pulley, otherwise yes.

guppymech

iTrader: (7)

LT4 springs work with the stock retainers and are a good replacement for high mile stock springs. If you went to the dealer for new LT1 springs they would give you LT4 springs.

BALLSS

LT4 springs were designed for lighter, sodium filled, LT4 valves. IMHO given the effort it takes to swap springs I would go with a better spring. Crane 10308-16 would be plug & play

The LT4 spring "new" may be slightly better than "old" LT1 springs...but with the heavier LT1 valves not a long term "upgrade"

bowtienut

iTrader: (1)

Yes, I would use those in a heartbeat if you're sticking with the stock cam.
I've used them on a couple of engines with ZZ3/ZZ4 cam revving to 6000.
For your application, they're as good of quality as you'll get from ANY aftermarket source.
No need to replace retainers and keepers.

Here....$42 shipped: http://www.ebay.com/itm/like/141383895366?lpid=82

Mystery Bird

iTrader: (7)

I would use them too on a stock cam. Can't beat the price.

JOHNNYMO

iTrader: (1)

Thanks... another question though... for a future cam upgrade, nothing huge, but better than the stock LT1 cam, will the LT4 springs be a good choice still?

bowtienut

iTrader: (1)

No. Anything beyond the stock cam with an LT1 intake manifold will need to rev more than 6000 to fully utilize the cam's powerband. I wouldn't try to use those springs over 6k with stock weight valves.

JOHNNYMO

iTrader: (1)

Ok, thanks again!! Got a line on a set of used headers and a Y.... TPIS brand from a forum member...once we work something out, Im ordering the springs and seals. Just thinking its better to do everything at once. I have the fitting/ air hose kit for the spark plug bores, so Ill do them on the car.

96capricemgr

iTrader: (1)

One poster got into discussing the LT1 valves being heavier than LT4 and that is true but is really only relevant when we are explaining why not to use LT4 springs with the HOT cam on an LT1.

As most have said the LT4 springs are great for an LT1 cam.

Far as future upgrades, valvesprings are a wear item, never buy springs to use now when looking to cam in the future.

BALLSS

as noted for anything other than stock cam the LT4 springs are not recommended (and personally I am not in favor of them just as a stock LT1 replacement, others feel differently) but as I mentioned earlier if going through the effort of a spring swap spend a few more $ as it sounds like you have intentions for further mods be it cam, 1:6 RR and or a tune which typically involves increasing RPM shift points so you want a spring that is not at the end of its abilities...which a LT4 spring would be with the further mods you ask (cam)

another option people have used is the Alex spring kit for AL heads

http://www.alexsparts.com/lt1-valve-...rs-locks-cups/

if just sticking with a stock cam, tune and rockers and $ are a concern than the GM LT4 springs are fairly cheap

http://www.summitracing.com/parts/na...5494/overview/

use a Viton full jacket valve stem seal. FelPro has them as does Alex on his site. Note he also sells them individually as you can tear them sometimes accidently on install so having one or two extra may come in handy for just a few $

JOHNNYMO

iTrader: (1)

Thanks a million guys. I kinda like the LT1 springs. $123.00 for the springs,retainers,locks and seals seems very reasonable to me. I spend much more on my LS6 springs when I bought those...seals alone were like $55.00 for that engine...

96capricemgr

iTrader: (1)

I am sure the Alex parts are quality springs BUT they have way more pressure than needed which is wasted power, and LT4 springs would reuse the stock retainers, locks etc saving a lot of money.

Like I said, don't buy springs for future upgrades as they are a wear item with aftermarket cams.