want to put GM Hot cam in stock 87 350TPI block, stock L98 heads,1.5rr and HSR....

GM Hot cam specs
279/287 duration
218/228 duration at .5 lift
.492/.492 lift with 1.5r
.525/.525 lift with 1.6r
lobe 112
1800-5800 RPM range

max lift at .492 is too much for stock L98 heads which max lift at .480 so im gona have to upgrade the springs/retainers for some extra lift... this is what im thinking about getting from summit, wats ur opinions or products i should use.

COMP CAM springs PN 981
summit part # CCA-981-16
1.254" outer diameter
1.150" bind height
0.880" inside diameter
417lbs/in spring rate

will these springs work and give me the extra lift that i am looking for? if so wat retainers should i use and if not wat springs and retainers would work to give me what i want...part #'s are appreciated. thanks

 

Yea, those springs will work. You'll want to pin the rocker studs, or pull them, and tap it for threaded studs as well. Collared required it to be machined, non collared doesn't.

I'd look at any basic 7* steel retainer, and .050" offset 7* locks. Also buy a pack of valve spring shims. By shimming up your valve spring .050", and using .050" taller offset locks, you end up keeping your retainer an extra .050" above the guide boss, which is typically where you'd see a problem with over .480 lift.

 

wow thanks alot sonix i couldnt have asked for a better reply. wat u mean "pin" the studs? i kno the studs are pressed in and screw in is always a better upgrade. in order for me to pull the studs the head will have to be taken off correct? bc i really didnt want to take the heads off, im looking to do all this in the car. and if i wasnt to touch the studs, add some .050 shims or better yet comp cams sells a kit with .015/.030/.060" shims, if i add the .060" shims with the stock studs will it still work...i didnt think so bc the stud is still the same height. so with the stock studs, the comp springs and retainers...will the HOT cam still work or no? thanks for the help

 

I have scoggin Dickies Z28 springs ( SD1007) . They are stock diameter . @ 1.8" ( installed height ) they have 120 lbs . @ 1.2" compressed they have 350 lbs . I was told for a hydrulic roller you don't want anymore than 350 lbs , or you can collapse the lifter . They told me these are good for 570 lift. But their listing says 550 lift. SO far so good for running a ZZ4 cam . The motor revs quick for a TPI .

 

i thought they discontinued those springs... you installed the z28 spriings on a stock L98 iron head and u got .550 lift? thats impossible but i hope its true, was their any machining to the head? so if i where to install the z28 springs on my stock heads i could get that lift, i really didnt want to go to screw in studs etc

 

-Vader did a write up on doing the mrgasket non collared studs, with the heads on the car. See if you can find that.
Or you can pin them. F-bird'88 has posted a how to a number of time, search for that. Basically you drill the boss, and the stud, and slam in a roll pin to lock the stud in.

And yea, you basically use the offset locks to keep the retainer higher. That will drop your spring pressure, so you shim up the springs to maintain it.

Usually the interference point isn't coil bind on the springs, but the retainer hitting the guide boss, hence that shim & offset lock trick.
1.8" installed height - 1.2" coil bind (this is the normal numbers for most 1.25" OD springs), gives .600" lift. Drop .050" for safety, and you're at .550" max safe lift. But .480" normally before the retainer hits the guide boss. Do the shim and offset thing, and you're up to .530" or so. Bingo.

 

i'll try the search thanks. and also do u know the part# for the offset locks? that would fit with the comp cam springs that i stated

wat if i wasnt to pin them or put in screw in studs...wat would happen with the setup i wanted to do? would they pull out?

 

scoggin sells a kit that has the Z28 springs, 0.550 max lift, includes locks and steel retainers that sells for 93$ part# KITSD1007

is this all i would need or would i also need the offset locks.

 

The Comp 981s will work just fine with that cam if used with 1.5 rocker arms- I have a firend who is doing exactly that right now. Comp rates them at .480" maxlift , but they will take .500 without any problem, even installed to their rather short (stock) height spec of 1.70". The real issue is retainer-to-guide clearance (with stock guide seal installed). You'll be hitting the retainer against the guide seal around .470. You can install taller locks but then you'll also have to shim the springs up to get back to a 1.70" installed height. Another low-buck/ghetto alternative is to grind the bottoms of the retainer a few hundredths to get the extra clearance you need.

Stock retainers work fine with 981 springs. You can buy the matching retainers for those springs from Comp but they won't give you any more retainer-to-guide clearance than stock.

 

Yep, I didn't even think you could grind the bottom of your retainers. Might be easier and less risky to whip out the angle grinder and shave off a bit off the top of the valve guide boss itself.
So that would work, or you could use taller locks and shim the springs.

Crane - CRN-99095-1 (cheapest at ~$30)
K motion - kmo-k-6140 ($40, and they're Kmotions for cryin' out loud)
Comp only makes them in 10*, which would mean you need 10* retainers as well. This bumps up the cost, and I don't think you have the spring force to need 10* locks.
The crane 7* ones mean you could reuse your stock retainers.

 

i didnt know u could grind the retainers, so if i was to go with the Z28 springs kit and just shave the retainers i could get .530 lift on the safe side right? then i could run my 1.6RR with the HOT cam which will give me .525/.525 max lift and will allow me to take full potential of the HOT cam.

how much HP increase should i see with the hotcam,1.6rr, and HSR?

i looked at those part #'s and it would be cheaper to buy this kit, do u kno the part #'s for the offset locks?

 

yea, I do know the part #'s for offset locks, see my previous post

 

lol yea i checked the cranes they arent offset at summit... are the Kmotions...i didnt check them at summit lol my bad
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ha i take that back im stupid sry lol...

so i get the locks, the shims, and the comp springs and i get .530 lift!!!! yeaaaaaaaaa so i can run 1.6rr's right? how much power we talkin here

 

i cant find .050" thick shims...i can only find .015, .030, and .060" shims from summit...

 

You can use a .015 and a .030", that'd be close enough. Or use a .060".
Look up articles on setting up valve train, shimming springs, etc. There's a procedure to this, so you can get the right spring force, and the right clearances.

You can use a drill press (or vice) and a bathroom scale to see what your pressures will be, then set them up to whatever is the spec for that cam. Try to get them all equal, or close to.

 

yeah my machienist didn't mention haveing to do anything exotci to make the SD1007 's fit

 

what about the GM LT4 springs, they're good for .525 lift and only 32.95. part no. 12495494


http://www.sdparts.com/product/12495...SpringKit.aspx

 

from what everyone has told me they the springs arent the cuplrit, its the retainer to guide clearance.... all u did was install the z28/LT4 springs and they will give u enought lift for .492 lift of the hot cam?

im getting mixed results here... so do i have to shim and install taller locks with the comp 981's/Z28/Lt4 springs inorder to allow the larger lift? or no? i dont wand to do any machine work to the head bc i will get rid of them when i get my 383 tgether. if i could just get away with just the springs then i will do that, but i need to know what will work

 

+1. i'm in need to know this as well

 

I just wrote up a nice long explanatory reply, then scrolled up to realize I had just retyped what I already put.
What's the problem here? What don't you understand? Install it, and measure it. See how much clearance you have with feeler gauges when you're on the nose of the cam. Basically rotate the engine over and find the place that gives the least clearance. Measure that. If you can't even get to that because you hit the retainer, then you definately need more room right?
So you've got the options listed above, grind boss, grind retainer, shim everything up.
Due to casting tolerances its hard for me (way over here) to see into your garage and tell you if you have the clearance. Gotta mock it up and find out.
Remember - springs are usually ok, they won't bind until ~.600" lift. It's the retainer-boss you worry about.

 

well some ppl are saying they didnt have to shim up the springs and buy offset locks. some ppl are saying they didnt have grind the bosses but did shim the springs. i dont wanna buy extra stuff or get more work done to the heads if i dont have to, you know what i mean? lol

i'll just have to go for it and take the heads down to the shop to get cut down and shim them...if i ever get to cam it this summer/fall

 

im about to swap out my valve spring on my aluminum L98 heads. I bought a ZZ3 350 a while back and im hoping to have all the cash together to finish rebuilding it this spring. i want to upgrade to something like a LT4 hot cam or something bigger. i did find LT4 springs unmodified would work just fine on my heads and is good for .530" lift with 1.6 rocker arms and for around $75 bucks you can buy everything you need to make it work. if i would of found a ZZ4 350 i would already have these springs. the LT4 hot cam kit comes with the LT4 spring kit, cam and 1.6 rocker arms for around $600