just wondering. all the magazines say .420 is the max lift the stock springs can handle. this seems kinda low to me.

 

Sure you're reading that right, that is awful low, aren't some of our stock cams about that lift,like on a L98?

 

Running a comp XE262H with no problems. .462/.469 I would not venture to far from that without milling the guide bosses down from what i have heard.

Lonnie

 

What vortecs are you using, cast or aluminum fastburns?

 

Cast iron with the stock springs. Pulls good to 5600. Again I think this cam is about the limit.

If you are looking to buy a set of vortec heads and want to use more cam, Scoggin Dickey chevrolet sells the heads with an upgraded spring package.

Lonnie

 

you are better off swapping in a new set of springs. there are plenty that drop right in without machining.

 

Lonnie,
Don't supose you'd share the specs on your cam?(LDA and lift @.050")

 

The springs that come on them are crap just like any other stock springs, they're replacement truck service parts not high-performance anything. But that's not the only problem, or even the biggest one.

The valve guides are so tall that the retainers hit the top of the guides at high lifts. Not all individual heads are the same; some can stand up to around .480" before the retainer smashes into the guide, some alot less. You never know until you measure the particular ones you have. You can machine them down; but that costs money, and the more money you spend on a set of them, the more of their single biggest advantage you lose: the fact that they're cheap. It makes more sense to figure out a combo that works within their limitations than it does to buy them and then try to turn them into a set of performance heads, because by the time you do that, you'll have more money in them than you would if you had just bought a set of real performance heads.

The cam that people seem to get the best results out of is the Comp XE268, which is about .480" on the exhaust. The XE262 is another one that seems to work well, it's a little milder (duh). Specs along with lots of other highly useful info are readily available on Comp's web site www.compcams.com

The S-D heads with the upgrade package are used ones, not that it's a big deal, but still... And their price is almost up to what a set of aluminum aftermarket ones go for.

 

The updated Scroggin-Dickey heads sell for about $660, thats a little more than half what a set of new aluminum heads will cost you. That's even $100 below other budget alluminum heads like World's Torquers, and I bet the Vortecs flow a lot better.

 

The Torquers are iron, too.

Plus you can't forget the cost of a Vortec intake manifold. Add on a couple hundred bucks to the cost of the heads

Suddenly, porting and polishing your own stock heads starts to look like a pretty good idea

 

Rancid87:

The comp cams XE262H is a Hydraulic flat tappet cam with 218/224 degrees duration @.050 and .462/.469 valve lift with 1.5 rockers. 110º lobe separation.

Lonnie

 

I have the SDPC machined vortec heads. They really are too expensive, but if you can find a set of stock vortec heads in a junkyard, and have the machined, you can probably keep the cost of the heads below $400. If you're running a carb, the intake manifold price isn't a big deal because you probably were going to buy an aftermarket manifold anyway, right? The self aligning rocker arms are cheap and easy to find. If you got the heads used, you can probably take the rocker arms with them, and the whole set, new, is only $50, or you can get roller rockers. I had to go the expensive route and get the scoggin-dickey heads because I couldn't have my car down for that long when swapping heads(I already had stock vortec heads on the motor with better springs). For what I wound up paying in the end, I could have gotten Dart Iron Eagles. However knowing what I know now, i could have had machined vortec heads for A LOT less than it cost me.

 

boogie,
all i mean is it's better to be safe than sorry.
, Rancid87

 

FWIW, Everything I have read says .480 lift. You can get a set of Z28 springs that should fit wthout a problem for like $60 and that would solve your spring problem (up to .500), but I beleive you DO run into retainer/guide interference somewhere in there as well.

 

You can buy the cutter to shorten the guide bosses your self
for about what a shop will charge ya. You can do the job with a 3/8 electric drill.
If you get the right cutter that maintains the .550" minor dia
of the seal you can reuse the stock vortec seals and retainers
and just add good stock dia. high perf springs.
Like the GM Z28 spring, comp 981, 941, Isky 235D, crane 99846
All these are good for .500" lift when installed at their recomended spring height. This ranges from 1.75" to 1.70" depending.....

I no longer recommend K-Motion K-700 springs. They are cheap
but break. Not worth it even if some one gives them to ya.
I believe if your valvetrain is set up right with reasonable net spring pressures like 100/110 seat and sub 300 open pressures,
that the pressed in studs are ok. (.500 or less lift) If you want to go beyond this
and/or go solid cam or roller than screw in studs are nessessary.

We recently made over 410+ dynoed hp on a throw together 350 vortec motor with a .450" HYD cam and stock rockers so never mind 1.6 rockers or that last bit of extra lift on a street motor. The numbers may look impressive but are just not nessessary.

 

Well, I found a place that sells new assembled Vortec heads. Not sure where these heads come from since they are so cheap, but the catalog says it is a GM parts waarehouse. they seem to have decent prices. At least on the heads.
* Bare $239.50

* All standard heads have:
-64cc chambers
-1.94"intake, 1.50"exhaust
-LT1 high velocity port design
-.480" lift (out of box)
-170cc intake runner volume
-must use extended reach spark plugs
-Requires vortec style intake, and self-alighning rocker arms
$249.50 base price. Anything beyond that is more.

* (The ones I'm getting)
Same as above, only it is drilled and tapped to be used with a
non-vortec intake. But needs .325" for the gasket. $279.50

* Standard with steam holes for 400ci SBC $264.50

* Standard with steam holes for 400 SB and tapped for non
Vortec intake. $294.50

* "Special performance Vortecs"
64cc chambers
1.94"int 1.50 exh.
ARP 3/8" screw in studs, GM guide plates
milled for .550" gross lift $386.00

* Same as above, except it can also be used with a non-vortec
intake. $416.00

 

Don't think that just because an older intake will "bolt up", that it will work the same. "Vortec" is GM-speak for "raised ports". In other words, even though the bolt holes can be easily made to line up, the ports in the heads are in a different place from the ports in your non-Vortec intake. So a set of Vortec heads without the Vortec intake will probably actually flow less than a set of non-Vortec heads with the same intake because the ports don't match up. All you get is some kind of bragging rights: "Yeah, I put these awesome Vortec heads on here, don't know why the car slowed down, guess I need to {insert tuning complaint here}, I haven't reprogrammed the chip yet, blah blah blah" when the real problem is you just shot yourself in the foot.

It takes less than 5 minutes a head with a hand drill to put the 400 steam holes in a head. So at $15 for 5 min, I would do that all day long, for a couple of days maybe even, if I could make the $180/hr they're charging.

Bare casting = $239.50
Assembled head = $249.50

What quality of valves, springs, retainers & locks are you getting for $10 a complete set? Hmmmmm....... I think I'll buy a truckload of those from them, and separate the parts off the castings, and sell them to mass-production rebuilders, I doubt even a shop that rebuilds 10,000 motors a year can buy all the hardware to turn a set of bare castings into runnable assemblies for $10 a head....

Note to self: do not participate in the Vortec buzzword racket as a retail consumer.

 

I had thought about the quality of the stuff used on the assembled heads. I understand what you are saying about that.
I had never thought about the intake lining up differently.
So what you are saying is that I should go with the standard bare heads, and just go with the Vortec intake and get some decent valve?
I don't care if the valves will last forever and that they are top quality stuff. I just want something affordable that will last. A little step up from stock valves would be fine with me. I'm not planning on a 100+ shot of nitrous on this thing. Just a higher performance daily driver than the LO3 I have now.

Thanks for the enlightenment on this stuff.

 

I bought the GMPP Fastburn aluminum vortec heads. They are drilled for both the old style intakes and the newer 8 bolt vortec ones. I also bought a Holley Stealth ram thinking it would work with these heads. Not a chance, when you lay the Stealth Ram in place it will not cover the intake ports on the heads with its outermost borders. I should have taken a pic of this to post showing what a mismatch it is. If the cast vortecs are similar to the fastburns only a Vortec intake will work and of course vortec intake gaskets gm number 12529094.

 

It is either Vortec heads and intake, or standard heads and standard intake. The two just DON'T mix.

If you go Vortec and its springs, stick with a cam that has .450 lift max.

Then you'll be happy

Otherwise, consider porting and polishing your stock heads. It is somewhat cheaper, by a couple hundred dollars, than ANY other route.