I think you are OK, but Lloyd is the expert

My Lunati stuff is installed and I don't know how much, if any, thicker the locators or retainers are vs say the 918's I had before. Like I said my spring pockets were machined down to accommodate a 1.800" spring height so setting them up at 1.780 was no issue for me

was your installed height the same with the Howard springs?

only variable would be the thickness of the locators & retainers between the two brands of spring kits if your Howard springs wound up at a higher installed height

IDK if ARP 3/8" RR studs are any stronger than OEM ones. Maybe they are. I went with 7/16" when I switched to Comp Pro Mags several years ago

 

According to the press release from Lunati, this kit should work on the LT1 as provided. I'm questioning it because it's so much spring pressure. They make no mention of rockers, cam material, or lifters. Just that it installs right in and works.

From all the research I've done, all locators are the same thickness; .100". But there are taller/shorter retainers and locks, plus shims for under the retainers to change install height.

The Installed height of the Howard's springs were 1.725" with taller retainers.

I'd like to go with 7/16 RR, but I don't have the means to justify the funds for new RR, studs, and pushrods right now.

What I really need is another car for a daily driver. LOL.

I'm going to have to install what I have as is for now. I need to get the car back on the road for work. If it messes some thing up, I'll contact Lunati. Summit has some TFS retainers that add .050" installed height, so I'll get those on order (out of stock of course, otherwise I'd have them today already) and swap them out when they get here. Maybe the +.050 locks will fit in the TFS retainers better. That could get me (theoretically) to 1.81" installed, which I would be happy with. Even adding .050" would help with my concerns.

 

I can't do it. I can't bring my self to install this kit as is. Ugh.

I measured the locks that came with the kit and they come in at 6.5° and they sit very nicely in the retainers. Then I measured the Howards Cams +.050" locks and they come in at 5.7° and will wobble in the Lunati retainers (but not in the Howards Cams retainers). It turns out the machine work on the Lunati's is much better than the Howards. The Howards were cheap ($11 for the set) to be fair, but they are not as round as they should be, this causes them to flair out just a tiny bit. But that flair is also just enough to cause issues.


I did however find some thinner spring locators! COMP Cams Valve Spring Locators 4682-16. They are 1.300" OD while my springs are 1.306", but I'm not too worried about .006" of overhang. That's a whooping .003"/side. They should be here Tuesday. I'm also ordering a new set of +.050" locks too, this time from Crower (fingers crossed). I can eat the $11 I spent on the Howard's Locks. Parts should arrive by Thursday.

 

did you happen to verify the valve spring height tool against a digital caliper?

set the spring mic at say 1.800" according to its markings (or any marking you chose) and then use digital calipers to see if it is exactly that. For example your tool says 1.700 but the digital caliper says it is 1.78 or 1.8xx or

It just sounds like based on your measurements you have a low installed height from what stock height is often reported (1.750)

Did Lloyd offer advice on your findings?

 

The install height I'm measuring is accurate, verified multiple times with digital calipers. I had a very hard time accepting the numbers I was seeing, I was convinced I was doing something wrong. Lloyd did e-mail me back with some awesome information. He said that rarely some LT1 heads end up with less install height and he has experienced the Lunati Duals coming in with low install heights like what I'm experiencing (1.710-1.720). The fix is taller locks or thinner locators.

I have my old heads still, and new valves..... I think I'll mock those up (untouched heads) and see what those measure in at with everything installed.

He also recommended I shoot for 1.750-1.780" installed height for my set up with those springs; 155-165 on the seat. With the .060" locators I should come in at 1.750 installed height and 175 on the seat (165-170 after run in) and 390 over the nose. That should set me up perfectly. And hopefully last me quite some time!

Thanks for all the input and help. I'll definitely update when I get everything installed. For now I get to enjoy the 9 speeds of surprisingly slow, sometimes jerky, but excellent gas mileage of the Chrysler 200 rental I have.

 

It is good you have been diligent & double checking, what are low installed height measurements.

The thinner locators and .050 retainers should bring you in on target.

Valve train is definitely something you don't want to be sloppy on

 

The +.050" Crower Locks (P/N: CRO-86107X1-16) locks fit the Lunati retainers beautifully! But it turns out my Valves are +.050" (or something, they have less stem beyond the lock groove than my stock ones do), the combination of the locks and valves only left me with about .040" clearance for the RR. I'm running SA RR's so this doesn't work. Now I have 2 sets of +.050 locks that don't work for me. Ugh. But, If I had stock type valves (where the groove sits further down the stem), I'd have no issues with the Crower Billet locks.

The Locators (P/N: CCA-4682-16) fit perfectly. Even though they are only 1.300" wide and the Springs are 1.306" wide, the Springs don't over hang the Locators at all. Not sure where they got the 1.306" measurement, but I think the base of the spring (because it's cut through the coil to make it flat) is a tiny bit thinner than the body, so it works great.

My installed height is now 1.755" which gives me a seat pressure of 174, after break in I should be 164-169 ish. And 388 over the nose; 378-383 after break in. those numbers look a lot better. I should have everything done by the end of the day today.

 

so you are saying your valves are not stock length and the groove for the locks is in a different (higher?) point on your valve making for a shorter install height (basically there is a shorter length of valve stem above the lock groove than stock valves?)?

FWIW back when I had my heads ported and larger valves put in (Ferra valves) and wanted to use the SA RR I had....I saw slight contact from the SA tabs hitting the locks. At the time these were Comp 987 springs with 10 degree retainers & locks. I switched to NSA RR

Good you found a parts combo that gets your installed height within a spec for good open & seat #'s. If you do find the SA tabs do hit on some with the locks with .040 clearance you have...than you will need to go NSA & guide plates

 

No, the valve stem over all length is the same, but the groove on the valves on my head are .040-.050" higher on the stem than my stock ones. That increased my install height. So, with those valves the Lunati kit still installed at only 1.715". With stock valve it would be been even shorter!

I measured the difference between the stock valves and the ones in my car, it came out to .040". With the Howard's .050 lock I had .010" clearance from the alignment tabs and the locks. With the Crower locks the alignment tabs hit the locks. If I had stock valves I could have gained another .010" in installed height over what I have now, with the crower locks.

Now I'm running everything in the Lunati kit minus the locators, using the comp cams locators that are .060" thick. Current install height is 1.755". I cant get any higher than that without machine work. If my heads ever come off again, I'll have the spring pockets machined down.

 

well it is good the Comp locators are thinner allowing a .040 higher install height...bringing you very close to reasonable open & seat pressure

Lloyd said the Lunati kit would barely break a sweat with my cam and should last 50k mi before needing to be checked for pressure

yeah it likely was a PIA checking, double checking, ordering alternate locators, retainers & locks to audition for best results

Glad you came up with a combo that works.

 

Thanks for all the help and input ******!

Everything is in with new seals and rocker studs. Runs good-ish. Held it at 2K rpm until warm for the break in and was getting the occasional pop in the exhaust; AFR is off now. I only did 1/8 turn past zero lash this time, but I wonder if the additional seat pressure is bleeding down the lifters and causing it to act like a smaller duration/lift cam throwing the tune off a bit? I'll be adjusting the tune throughout the week.

I did measure one more time after cranking the engine over a couple times, gained another .005" install height with everything fully seated; bringing me to 1.760" installed height. So after break in I should be right around 160-165 on the seat and 376-381 over the nose. The engine does rev a bit quicker, idles smoother (I think this is related to the bleed down), and sounds stronger too. To be fair though, I was getting valve float at 6K with the last set of Howards 98215's. Felt like I hit a speed limiter at 6K, that's what prompted this spring change. I also found 2 more broken dampers, but no damage (other than a scraped up seal) though. So got lucky there.

So after 26K miles and 32 Howards 98215's, set up to their max on a fairly aggressive cam profile, I had 14 broken spring dampers and 1 broken spring. Not too bad for $120 springs. This set should go for 30-50K according to Lloyd as I'm set up, and ran me $280 ($703 if you include the both sets of locks that didn't work and the 10 days of Rental car). But, next time I can get just the springs for $150! I'll take it. I may order a spare set to have on hand at about 15K miles just in case though.

For those that are interested here's all the parts that will work together.

Lunati 73925K5 Kit (Locks, Retainers, Locators, Springs, and Seals)
Crower 86107X1-16 (+0.050" Locks, these fit the Lunati retainers perfectly. But, depending on your valves and RR's may not work for the set up)
Comp Cams 4682-16 (.060" thick Locators, these fit the head and springs perfectly)

On a stock head with stock Valves, this should get you an installed height range of 1.850" to 1.715". Of course measure your stuff first before you order anything. If I had NSA RR I could've added another .050" to my install height. I'm still kicking my self for that one.