When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
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!
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/
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.
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.
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?
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.
7 Most Reliable High-Performance Engines GM Has Ever Built
Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Another valve spring question 
