How do i know if i need the self aligning ones or non self aligning? I have a 4 bolt 350 with a flat tappet cam and oem chevy heads. cam is very mild. looking to get some roller tip rockers arms.

 

pull a valve cover off and check the hole which the pushrods go through. if they barely fit side to side then non self aligning but if its a big hole then youll need either self aligners rockers or guide plates.

 

ok, so really this is a matter of keeping the pushrod aligned correctly with little play.. So the hole in which the pushrod feeds through on the head is the one i need to look at correct? And if the pushrod looks like it is snug with no room to play then i don't need self aligning. righ tso far?

 

Correct.
If it's a slot then normal rockers, if it's a round hole, then self aligning.

Pre 1987 factory heads typically used normal rockers, after that, or aftermarket heads usually need the SA rockers (or guideplates).

 

i'll have to take a valve cover off and look, but i know the heads are pre 87.

 

one more quick question, should i buy new pushrods when i change the rocker arms? if so is there a standard size, or does it vary from engine?

 

I wouldn't bother.

If you feel like it, you can get a pushrod length checking tool and use that, then get custom made ones that are EXACTLY the right length. But if you've got a normal (non-custom) shortblock then normal pushrods should be "right".

 

I thought that myth was busted. GM used SA rockers with narrow slots. I'd call the rocker mfg and ask what they say.

 

Uhh, yea, that's right. Ok, well most of the time the slots were used with normal non SA rockers.
And if you have giant gaping holes, you CAN'T use non-SA rockers. That's the gist of it.

 

Not from 87 and later. Here's a pic of 350 TPI 083 heads with the slots. You can see from the pic that they are narrower than the studs. i believe these heads also came with SA rockers.

 

Ok, so like I said earlier:
pre 1987 - non-SA rockers
Post 1987 - SA rockers

Right?

 

so the first pic was an example of a tight slot pushrod hole that doesn't need self aligning rockers? anyone have an example of the two.. just to make it perfectly clear..

 

Both pictures are examples of the tight pushrod slot.
The other one is.... picture a 1/2" drill bit going through the center of that slot. That's what it would look like. It's REALLY easy to tell the difference, one is a giant ROUND hole, the other is a SLOT.

 

Yes, but is there any reason to say pre 1987 heads with the slots use non SA rockers? Its true they didn't come with them, but GM didn't have any prior to 87. I don't see any reason to make a distintion. Are you aware of any reason to say "pre 1987 - non-SA rockers" other than they weren't available at that time?

 

Oh, I see what you're driving at. I suppose not. Typically self aligning is more expensive, and if they didn't need them from the factory, then I wouldn't go out of my way to get them.

 

If you need self alligning rockers, you can also use guideplates with normal rockers instead. Guideplates mean you should use hardened pushrods, though. So keep that in mind.

 

hear is a pic of a 96 head
im using these heads on my build so would i want SA rockers?

 

That head has guideplates, so you want non-SA rockers.

 

could i still use the SA rockers or would that hurt me in any way?

 

The two alignment methods might disagree and you'd have things binding.

 

i will defently go with the non SA rockers now thanks alot for ur help

 

cool i have a pretty clear answer now and understanding of self aligning rockers. thanks guys.