Stoopalini

In that thread, Lloyd says:

So how do you adjust the rocker to be centered on the valve stem tip if it is off-center?

Thomas.

wrd1972

I think we might be getting up-down axis and left-right axis mixed up here. As far as I know the pushrod length affects the up-down axis and the roller sweep. The guide plate controls the left-right axis. I would imagine that the left-right axis has limited adjustability unless you have Isky adjustable plates.

97s10ondubs

Guess Ill give them a shot with my new heads.

2QUIK6

Thats what I was thinking since they are not that difficult to check periodically and its not an expensive part. To me the Isky plates are going to be difficult to adjust under the cowl with the motor in. I could use some mirrors to help with centering, but sometimes what looks centered in the mirror isn't. I could use the Isky's in the truck however since they are all easy to get to and see to line up.

aboatguy

AI sold me some hardened guide plates that seem to work better than my old GMPPs

Stl94LT1

I installed the Trickflow guide plates a couple of weeks ago, and they align the rockers near perfect.

wrd1972

Maybe you guys can post some photos of the AI and trick flow guide plates.

Stl94LT1

I can probably get an installed pic if you would like?

Here's a pic off Summit's site of the Trickflows.

dhirocz

I had this problem before. I had a Vortec 350 in an old trans am where I couldnt figure out why it was losing it's valve adjustment... damn press in studs pulling out of the heads After getting those replaced, I went with a NSA 1.6 rocker arm and GMPP guideplates. The make a long story short they SUCK. I went through not one but two sets.

After looking at them, I figured the cause was a combination of poor valvetrain geometry and using a non-hardened steel in the guideplate. If you look at the rocker tips, at least one of the two will be off center... not good. This makes the pushrod sit cockeyed, digging into the guideplate. The pushrods need to be STRAIGHT to minimize this. I noticed the guideplates were a little off. This will also make you loose a little lift... not much though.

To fix this, it's been said. Adjustable guideplates. Put them in, set them where they need to be, then tack weld them... remove them and weld em up nice. I even stamp them to a location in the head to keep them on the same pair of valves. Works like a champ! Worth every penny.

I've been taught that you either use self aligning rockers and you can use either a standard or hardened pushrod (stock or mild setups) or a NSA rocker arm and guideplates with hardened pushrods(high perf). Using non hardened pushrods with guideplates usually causes significant pushrod wear, so I wonder wtf GM was thinking? Must have been a factory cost effectiveness thing, I dunno...

Stoopalini

Well, I got the heads back from the machine shop, and had a closer look at the guideplates.



I have to agree with previous posters, that these DO NOT have the correct spacing for LT1 heads. If you look, every singe guide is worn on the outside only. It looks like the guides in the GMPP plates are too close together. I'm sure if I were to have a new set hardened, this wouldn't happen, but I don't like the idea of solving a symptom instead of the problem.

I suppose I'll be ordering the trickflows, as they seem to have the notches cut for the LT4 valvecover supports; I just wonder if they have the same spacing. Does anyone have one of each, and can compare them?

Thomas.

2QUIK6

I haven't ordered the trickflows yet...not sure I'm going to, I may just go with the Isky adj on my truck. The '95 TA has the GMPP plates, but the valve train has made a terrible ticking noise at certain rpms.
Checked the valve guides and geometery, looks all good except for the rockers being just slightly cocked to one side due to the GMPP plates...
I'm thinking this may be causing the pr to slap against the plate causing the noise.
Just for kicks I'm going to get some SA rockers and remove the plates, I'll have to get the smaller studs too...but I'm not using a high lift cam anymore and won't be revving past 6k..good enough for the factory it will be good enough for this application.