Casey_Butt

Hi, I just bought a set of 601 heads for my 1988 L03. I know these heads have the narrow pushrod guide slots and old-style bolt pattern for the valve covers and I have a few questions.

1.) How hard a job is it to drill out the pushrod guide holes to accomodate my L03 stock self-aligning roller rockers? It doesn't seem like much, but do pushrod guide holes need to be specially surfaced or anything. Is it even necessary to grind them at all, as I've heard of people running both the slot-type pushrod guides and SA rockers (in fact, I think even GM put them out like this).

2.) Will I need hardened pushrods? I've been told that I don't.

3.) How much lift will these heads tolerate? I've got heavier springs coming but I'm wondering about retainer to valve stem clearance and limitations of the stock press-in rocker arm studs.

Thanks for any guidance you can give me.

--
Casey

Stekman

Self aligning rockers dont have as much to do with the pushrod hole as it does with the valve tip (not saying they dont have anything to do period, just not as much). The roller on the rocker has a recessed center to 'cradle' the tip of the valve, therefore centering it. And of course you have the narrow guideslots. Those heads were not intended to be used with self aligning rocker arms. The guide slots were the factorys method of keeping the pushrod in place and, in turn, keeping the rocker over the valve tip.

1.) Not very hard. I used a rotary file and a drill. Do not mix guideplates and SA rockers. You only need 1 method of centering the rocker arm over the valve.

2.) only if you run guideplates. (See above statement)

3.) pull out studs seem to be dangerous when anything over about .480" lift is used. Of course, if you run beefier springs, it should be a give in that you use scre in studs.

Casey_Butt

Is there any difference in valve tips and retainers for the non-aligning versus the self-aligning rockers? In other words, as far as the rocker tip itself is concerned, are they interchangable?

YenkoZL1

Im pretty sure when running roller rockers you would need hardened pushrods. Like Comps Hi-Tech rods. But then again Im not sure cause I bought my hardened pushrods because of my guide plates. I think you'd need hardened pushrods if your running guideplates not just RollerRockers. I hope you can make sense out of this. I just kinda confused myself here.

Stekman

i BELIEVE that the difference is primarily in the retainer. I am bad ant explaining, but i will do my best.

For non-self aligning, the part that holds the spring is more or less flush with the top of the center part is for the locks. This "conceals" the tip mor or less in the retainer so to speak.

Self aligning rockers, the part that does the retaining is stepped down a slight bit from the center area. This step exposes the tip of the valve when the locks are installed.

I haven't taken a very close look at them ot compared the valves at all, but that seems to be the difference between the factory vortec retainers (vortecs too, are SA) and the retainers i have installed on my 416's. Dont quote me on those differences, though.

*Edit* hardened pushrods are really only needed for guideplates. They prevent excessive side wear as the pushord goes up and down and rubs against the guideplates.

ME Leigh

Your L03 should not have SA rockers the SA rockers started with the vortec heads i believe.

You can't run both, its either one other the other, or you will have major problem i.e. breakage. Also you only need hardened pushrods if you are running guide plates. SA rockers have little lips on the side that run parallel with the rocker body, this holds the rocker on the valve tip.

five7kid

iTrader: (14)

Here I thought SA started in 1988...

The hardened pushrods are only required for guideplates, which you won't use with SA rockers, as stated.

The difference b/t SA and non-SA is the rocker itself. The valves are the same, but you need to make sure the retainer doesn't "hide" the tip of the valve stem, as mentioned.