MyShibbyZ28

I was looking at the Comp Cams Pro Magnum roller rockers, and it says they're non-self aligning and it'll need hardened pushrods with guide plates. What size are the stock LT1 pushrods so i know what to get? Along with guide plates, anything special with them? And should i change the springs? if so to what? I plan on doing this over the winter while my car sits.

ShibbyZ

SStrokerAce

7.200" long.

7940-16 would be my first choice
7608-16 2nd choice

simple

valve springs are a wear item and fatigue over time
changing them should help with valve control throughout the rpm range
and if a rocker with a larger ratio then stock is being used then upgrading springs would be on the plus side of things
you might be pleasantly surprised at how much just a set of new springs could help!

i have read numerous threads from numerous people about guide plates for our heads
ALOT of people say too use the GMPP guideplates for the vortec heads because of different valve spacing (supposedly LT1 and Vortec heads share this)
Comp cams doesnt seem too recognize that (if its true at all) i have no idea if it is too be honest with you. they dont specify there plates for use on Vortec heads...

but i ordered/use the GM guide plates and have been fine so far...

blackztpi

certain years of lt1s already have hardened pushrods. i know the 94's do.

MyShibbyZ28

Certain years came stock with hardened pushrods? Mine's a 94 and if they did then that's that much more money i save. So far what i've gained in knowledge is that non-self aligning rockers fit better under the stock valve covers and also don't make as much noise, so that's why i was going to go with them. Second i found out i should upgrade my springs to a stronger or more resistant spring. I have no clue what the open or seat load means on a spring, or what rate i should get, nothing. I heard 308# springs are a good upgrade or are stock, i don't know. I have no clue when it comes to springs. So some help there would be well.....helpfull.

Pro Mag 1.6 Roller Rockers
GM guide plates
Springs (don't know what kind to get)

That's all i should need to rebuild my valvetrain right? since 94's already came stock with hardened pushrods?

ShibbyZ

simple

comp 918 beehives with steel retainers
comp 985 or 987 with titanium retainers (or steel for less $)
Crane 10308
combination motorsports 612 springs with their chromemoly retainers....
if you arent doing an aftermarket cam, the GM Hotcam springs would probably workout good too

i've had good luck with the 985's so far

i would also recommend ARP rocker studs in which ever size you need for the rockers you are going with

MyShibbyZ28

So am i trying to find a spring with a Rate of about 330-360 ft/lbs? The 985's say they have 333 ft/lbs. Also, what does the degree mean on the retainer? I think i'd like to get these springs here, the second ones down, 987. think they'll get the job done? Also about the retainers, does it really matter what quality it is? It doesn't have to be titanium or chromemoly right? steal works fine?

MyShibbyZ28

Another thing i just thought of, the stock rocker studs are 3/8's of an inch right? so i that way i don't have to replace them when i order the wrong size rocker arm.

Transamdriver

Yes, the stock studs are 3/8".

MyShibbyZ28

I just had a thought, can i just go straight to 1.7 with stronger springs. I don't plan on getting a bigger cam for this because 1. not enough money 2. not enough knowledge 3. not enough space. So i'm trying to get as much power out of this thing without swapping the cam. So can i just get 1.7 roller rockers with the 7/16" screw in stud and stronger springs with tall valve covers?

SStrokerAce

yep you can do that...

I would still use the beehives for that.

Bret

MyShibbyZ28

Cool, what do you think my lift would be increased by if i went to 1.7's? Also, since they don't make 1.7's for SBC, the BBC ones will still work right? just need the right sized stud?

simple

take the lift, divide by 1.5 and then multiply the new number by 1.7 and thats the new lift number
i'm not sure which 1.7's people are using....

steel retainers would work but titanium would be optimal because of less mass and that means quicker revs, more rpm, less stress and more stability at rpm

MyShibbyZ28

Ok, all you guys have been a great help in helping me understand valvetrain. Thanks, but here are some questions that i still am wondering about.

1. Does it matter if i use big block rockers on a small block as long as i have tall enough valve covers?
2. Can i overdo it? as in, can i get to a ratio that will start to hurt my engine/performance?
3. Did 94 camaro's already come stock with hardened pushrods? if so i'm not going to buy any
4. Can i use the LS1 roller rockers that are 1.85 if i want to?
5. Is going from .447 lift to .536 too much? That'd be a change from 1.5 rockers to 1.8, if so, then i'm going to 1.7's which would move the lift to .506

and finally, 6. Couldn't going to a bigger lift without getting a longer duration be bad, like the piston might not get all the air out on the exhaust or something? Or am i just making stuff up?

ShibbyZ

SStrokerAce

Not really but I would run a rocker arm made for a SBC anyways.

Yes if you don't match everything else up with it


Yes, but you have to remember that a rocker arm multiplies the lift AND the spring pressure. Your new springs will have more pressure and the new rocker arms will put more force on the pushrods so you really do need a better pushrod here... you can do it the other way but you can run into float and bounce with the valve because of the pushrod deflecting and all hell can break loose.

nope, not unless you want to do a lot of work to them

1.7's should be good

No as long as the spring can handle the lift you are fine.

bret