Will the Vortec V6 engine respond to mods like the V8 does? I wondered if I could slip in a set of 1.6 ratio rockers on my 93 Blazer's Vortec 4.3L? If I order a set for the V8, aren't they the same as long as they're for the late model engines?

[This message has been edited by Drg racr (edited May 03, 2005).]

The 4.3 is basically a 350 with two of the center cylinders cut out, so yes, most of what works on the 350 will work on the 4.3L.

So, maybe I'll order a set of roller rockers for it and see if it does any good. The motor makes good power now, but I want more! It's a new Jasper engine, has maybe 10000 miles on it.

The 4.3L Vortec in a Blazer. This reminds me of the time my buddy and I blew one in a '98 with 150k miles on it. Lifter shot out one end and a pushrod out the other. Massive holes in that one. If you redline one, then here a clicking, dont continue to off road with it for two more days.

Hold up. The 4.3 Vortec heads don't take standard SBC V8 rocker arms. They use weird 10mm non-adjustable style pedestal rockers & studs.

If you want a bolt-in solution that allows you to swap over to standard SBC V8 adjustable rocker arms (in your choice of ratio) you'll need to buy a set of conversion studs that are 10mm on the bottom threads and 3/8" fine on the top threads. You can get them from ARP (Summit, etc.) but they'll set you back over $100 for a set of 12- and you still haven't bought rocker arms yet!!

Also, your Vortec motor probably uses centerbolt style PLASTIC valve covers. I don't know if you're going to get a standard (fat) aluminum roller rocker to fit under them. You might have to get a set of Crane Gold narrow-style rockers, which ain't cheap.

Last issue.... guideplates or self-aligning rockers?

Natively the heads use self-aligning rockers. However, your choices of rocker arms are limited (and expensive) for self-aligning jobbies. Again, Crane Gold narrow self-aligning units are the only ones that come to mind that would definitely fit under the valve covers. Unless somebody makes a cheap set of V8-style stamped steel self aligning rockers in a 1.6 ratio. I don't know if anyone does, but I haven't gone looking for them.

So you now ask yourself..... self, why wouldn't I just put on some V8 guideplates when I install the new studs, right? Sorry, the valve spacing on the Vortec heads is EVER SO SLIGHTLY DIFFERENT than a standard SBC V8 and your rocker tips will end up 1/2 way off the side of the valve tip. You can use ADJUSTABLE SBC V8 guideplates available from Isky, however, if you want to go this route.

End of the day..... you're staring down some serious money to do this. Probably not a good bang-for-the-buck bolt on upgrade.


[This message has been edited by Damon (edited May 03, 2005).]

I just thought of one more problem......

The pushrod holes in SOME Vortec heads just won't take a 1.6 rocker arm. The pushrod rides agains the bottom of the pushrod hole when you put on the high ratio rockers and it just won't work. And there's no way to know if yours will clear or not until you've already got it ripped apart to put the rockers on.

Now, you can use a hand-file and open them up while the motor is still on the car IF you take the intake off, put a rag underneath in the lifter valley and be REALLY ANAL about any of the filings that drop into the lifter valley and/or valve deck.

You starting to get the feeling this is not as easy a project as it may appear to be at first?

That's the info I needed. I wasn't sure if the rocker arms or ajoining components were similar or not. Thanks Damon for clearing it up. For now, I'll just stick with what it has now.