Hey guys, new to the forum and first post. Looking for valve spring upgrade part numbers and 1.6 rockers. All the previous part numbers I have found with my searches are discontinued.

Car is a 95 Z28 M6 all stock with 235K.
Thanks in advance!

 

I don't recall what specs they are, but if you call any major spring manufacturer they should be able to sell you what you need.

 

Try the PAC 1218 springs, amazing spring for the lt1 head.

 

Would that require new retaining hardware? Valve covers etc?

 

If Aluminum heads, get these

#73925-16 Valve Spring Kit (GM LT1 '92-'97 Aluminum Head Engines, 630" Lift, Steel Retainers) - Lunati®, LLC. (lunatipower.com)

Comp "Ultra" Pro Mag RR are considered to be very good. Many do chose to go the 7/16" version so new RR studs are required, ARP

You will need to make a minor valve cover mod by trimming the intake side of the X brace.

 

Also, ensure your adjusting nuts are not of the tall variety. They will not work with stock valve covers.

 

If your car is stock and you aren't changing out the camshaft, then it makes zero sense to go with the PAC or Lunati options since you will be putting way too much spring in the engine and can run into a number of issues like spring surge, decreased power, and valvetrain failures from the increased spring pressures.

With 1.6 rockers, you'll basically be at .480/.490 lift with the stock cam. There are a few options:

- Isky 235D: I think you will need different locators as the stock LT1 locators/seats are a touch too small. These are good to .550 lift. Stock retainers and keepers should fit.
https://www.summitracing.com/parts/isk-235d

- PBM 3000: These are good to .500", and are probably the ones I would go with if you don't plan on going with a higher lift camshaft. Verify the spring fits the stock locator. Stock retainers and keepers should fit.
http://www.pbm-erson.com/Catalog/Ers...prings/PBM3000

-Alex's Parts Vsk4i21-R: These are good to .530" lift and come with everything needed to install. I've used Alex's valve springs before with good results in a mild setup with Vortec heads, and they've been going fine for 6 years. I wouldn't have an issue using their stuff again.
https://www.alexsparts.com/lt1-valve...ift-vsk4i21-r/

-GM LS6/LS3 beehive springs: You will need the Comp Cams 787-16 retainer with these springs.
https://www.summitracing.com/parts/nal-19420455


As always, measure and verify your spring heights as each of the above springs have a different recommended install height, and verify your pushrod lengths with the new rockers.

 

LE Custom billet cam, PAC 1218s, new locks, retainers, and 1.6 roller rockers are the best way to go. The crane lt4 1.6 roller rockers are nice pieces.
Then you gotta get headers to let it breath, and a tune.
lots of options

 

Wow thanks for all the replies! Cam isn't an option at the moment. Headers are on the way. Car is new to me so just doing a reseal of all Gaskets due to oil leaks everywhere. Thought i would consider new springs while I'm in there. Only a couple months til the snow melts and I can drive this thing again!

 

Valve springs are a wear item and the stock LT1 springs generally are done around 60k mi beyond 5200 rpm

The Alex spring was a budget go to for a stock cam replacement spring

The Crane 10309 spring is very good but seems to be extinct now

Lloyd Elliott recommended and sold to me the LT1 Lunati kit I noted. I would regard his advice as expert...

 

Lloyds advice is right on the money. I have used Pac1218s in the past and they are garbage. I have actually broken 2 different beehive springs. A Pac1218 and a IIRC Crane spring that was in my Dodge 4.7L with 218/224 cams. A friend of mine also experienced valve float with LS6 springs at 6,000 rpm in his 6.0L with a Summit truck cam they claim is good for alot more rpm. It now has dual springs. You could not pay me to use a single or beehive spring in an engine over 5K rpm now.

 

The Lunati 73925 is an excellent spring when the application requires it. A stock camshaft does not require that much spring.

 

Another vote for LS6 beehive springs & comp 787 retainers, I prefer the tool steel retainers myself but prices are getting high on those.

 

PAC is basically the best spring company out there, just ask Nascar.
double springs have there place with super aggressive cams.
beehives work excellent for the typical street cam. Just make sure you are buying made in USA springs and not over seas junk.
and lunati is not all it's cracked up to be anymore, they are also sell outs.

 

PSI Springs

 

I was under the impression that on an LT1 you needed to do some modification to fit LS valve springs.

https://www.onallcylinders.com/2017/...ylinder-heads/

 

Found a set of LT4 springs online. All specs appear correct except for spring rate of 332 lb/inch? From what I've read it should be in the 130ish range?

 

New or used, where'd you find them? New LT4 springs are around $500 now. Ridiculous.

 

Found them new on a vette site for $62 plus $40 shipping. So you're saying that's a good deal then?