I'm looking into LS1 or LS6 valve springs but I think the O.D. of these springs is 1.29" Aren't the LB9 spring pockets 1.25"?

Also I believe the recommended installed height of the LS1 spring is 1.8" how does that compare with stock LB9 valve springs?

Can these springs be installed without machinging my heads?

Thanks.

 

not much differance between 1.25 and 1.29 so they might and they might not. why are you wanting to run them when there's so many springs that'll fall right into place and are designed for your application. if they stock gm springs i'd trash them anyway since gm springs aren't known to be of high quality. most gm springs run an installed height of around 1.70.

 

081 Heads? In a word, no. The spring pockets barely fit the OEM 1.23" springs.

 

Maybe, maybe not. An extra .040" doesn't sound like much, but stock spring pockets aren't machined much larger than the stock springs (1.25"). You'd have to try it.

Also, stock installed spring height is nominally 1.70" on those heads. But that's using the stock retainers and locks (including the rotator/retainer on the exhaust- it's thicker than the standard one on the intake side but the exhaust spring pockets are machined about 1/16" deeper to compensate). Start playing mix-n-match with retainers and locks and you might end up pretty far off.

If you're looking for a drop-in replacement spring that's good up to .500" lift for a flat tappet or mild roller cam then get a set of Crane 99848 springs. They'll drop right in and work with all the stock stuff, including the exhaust rotator/retainers.

You'll run into problems with retainer-to-guide seal clearance well before you max out the .500" springs on those heads (usually around .470" they contact eachother).

 

Thanks for the feedback guys.

Vader,

You might not remember but, you actually refered my to the guy in northern IL who sold me these heads. I got the set for $40 and had them "reworked" but
the "*#^hole" at the machine shop must have just re-installed the stock springs and charged me for new ones because the springs are the weak link in the valvetrain. The valves start to float at about 5,500 RPM and I think that my cam is good for at least another 500 RPM.

ede,

There are three reasons why I'm looking at the LS1 (actually LS6) springs. The first is that they have the higher spring pressure that I need. Second, they are a beehive shape. This article explains the distinct advantages over a regular shaped spring:

http://www.babcox.com/editorial/ar/eb50354.htm

Third, they are quite a bit less expensive than the equivilent Comp Cams spring set. I could order a new set of LS6 springs from GM for about $45 whereas the comp cams beehive springs run about $230.

Vader, you said that the 081(LB9) heads come stock with 1.23" springs. Is this the same as the 350 heads like L98's for example? All of the aftermarket springs that are reccomended for the SBC are listed as having 1.25" OD. Will the 1.25" OD fit the 081 (LB9) heads?

 

just another option to look into, lunati 73943 springs. 1.25" OD, specs are very similar to comp986 DUAL springs.

 

I know they are quoted as 1.25" springs, but they don't always quite measure that at the coils. I've tried to install 1.25" springs in '416 heads and have had interference so the springs didn't seat fully.

Perhaps they just installed stock replacement springs. Even new, they aren't much to get excited about.

FWIW, who did the work (so I can avoid them)?

 

Vader,

The heads were reconditioned by Performance Head in Madison, WI on Greenway Cross.

Supposedly, he shaved them down .020" installed new Ferrea back cut and swirl polished intake and exhaust valves and new valve springs that he said "are good for up to .510" lift up to about 7,500 RPM". B.S.

I asked for the old parts back (Springs, Valves) prior to having the work done but when I went to pick up the heads he said the old parts had been thrown away. Now that I think about it, he probably just hot tanked the heads, spray painted them, and charged me the $384 for all of the parts and labor he quoted. I wish I would have removed and inspected the "new" intake and exhaust valves before installing the heads. I would have been able to tell if they were in fact back cut valves. That's the only way I'd know for sure.

I just got a digital camera so I thought I'd attach a couple of photos:







Lance