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may have my vortec heads.. need help

RootBreaker

RootBreaker

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Ok so I missed an auction... $481 was my bid.. vortec heads "906" which people say some have problems.. but these had pro comp springs, retainers, etc.. good to .510 lift cam.... plus intake.... anyway missed it..
the guy said the guy still hasnt paid him so I will know soon if he will sell them to me.... he legally or ebayilly had to wait till thursday... so im waiting...
so if i get that there is no questions...


now on the side note I found a set locally...
vortec stock 1996 heads.. just asked what the casting number was...
so since these are stock with 50k miles.... some say that those heads are good to .450 lift and some say .480 lift and some say .475 lift...
anyone know for sure?????
the cam I am looking at is .474 so the first auction would have been nice as I dont have anything to worry about...
but these stockers.... if .450 is max..... cant get the xtreme 4x4 cam then...
how hard would it be to get the heads to accept the .474 lift cam?

I appologize for my ignorance on intelligence on this subject... :haha:

If I cannot figure this out... im just going to drop the stockers on with a intake and leave the cam alone for now....

but if all it takes is z28 springs (what year) and lt4 retainers...... then Ill do it....


just hope the guy gets back to me with the first...... .510 would be plentyful.... also with a .474 lift cam I should be able to go 1.6 or 1.7 rollers in teh future huh????? :bow:
 
906 being the undesirable vortecs is a myth. It was first noted in Chevy High performance Magazine and then later corrected. having obtained a set of each casting # I can't visibly see a difference between the two where they said there was one.

The range for lift capability is widely noted as you said from as little as .450 to as much as .490. One set I got I gave to my dad for his Nomad and he sent them out to have the spring pockets enlarged for z28 sized springs and the guide boss machined down for pc seals. That elminates the retainer to guide boss clearance that Vortecs are so noted for. Ran him $100 to do the set plus the cost of the springs. Now the cam he intends to run is tame (onl L79 grind, .448" lift), but being an engineer he wanted a large margin of clearance just to be safe even though he could have left them alone with that lift. I plan on doing the same to my Vortec's too.

Now that being said, my buddy I got one of the sets of vortec's from has a set on a little 355 in his 2wd S10. Nothing done to the heads and he is running .500 lift and spins it to 6 grand. How he hasn't smacked the retainers into the guides I don't know. I have seen him run and when he has hit 6 grand when I'm there I've never heard any valvetrain noises. That's pushing your luck in my opinion, but he's had it that way for 3 years now and no problems. *****your results may vary*****

.474 lift should work on stock vortec's but if you got the money add the larger springs and get the guides machined down for that extra margin of clearance. Oh and as for the Rocker ratio, remember that the increased ratio adds to your net lift from the cam. Moving to 1.7's could put you closer to having an issue. If you do the work first, 1.7's shouldn't be an issue, but on stock heads with .474 lift it might.
 
Comp has those new beehive shaped springs that allow running higher lift without having to machine the heads to accept a larger diameter spring.
 
Have you looked at the price of those?

I'd still be heading for new aftermarket...
 
Ive seen the difference in casting numbers. I have a set of 906 and they are fine, but some of the 906 heads that went on heavy duty trucks have been machined to accept an oversized exhaust seat. if its there, you will see it. My 906 heads are fine, and look like the other sets other than the hump instead of three peaks casting mark.
 
my casting #'s

are 12558060...i ordered them straight from gm performance parts via jegs...they are suppossed to have sodium filled exhaust and out flow phase II bowtie out of the box i've looked for that casting # but can't find it any where but they came in there own boxes with big gm performance parts stickers on the end of the boxes. they have the 3 triangle casting marks on the end of each head
 
The "three peaks" is 060 heads, those are the good ones no matter what... especially if you got them from gmpp
 
thebigdaddyof2 said:
Vortec info from Salee Chevrolet:

http://www.sallee-chevrolet.com/Cylinder_Heads/Vortec.html
Click to expand...

So $160 for springs/retainers (from Jegs price list) and $40 to install them from Sallee, now you are at what, $700 for a pair of otherwise stock GM heads? How much more does it cost to get heads with better/cheaper/more common springs, no interference issues, screw in studs, thicker castings, "standard" intake bolt pattern, etc ? $100? (easily made up if you don't have to change intakes from your current one)

Just pointing out the costs associated with bringing Vortecs up performance-wise.
 
Not a bad price, I still think going aftermarket heads is a better bet unless you JUST want to replace your heads and leave the camshaft stock.
 
so many people say so many different things....

sled_dog's comment is what im looking for.. although most components are gonna be different.. close but different...

he said... stock springs work till .470/.480, depends where you look

so a .474/.474 will be pusing it on the intake side... but gonna try.... :wink1:

gonna get heads saturday.... order cam/gaskets/intake from summitracing next week!!!!! just gotta look at the heads first...
 
Yeah, but whats the seat pressure on those stock springs? Something like 80 IIRC. My roller cam, which admittedly needs more seat pressure than flat tappet (but is still a very mild grind) *required* the use of better springs.

You say you are going to try it, but you need to check with the cam maker before you just slap it in. You are wasting time and money if you don't get the specs from the cam maker first.

For instance, the Comp Cams 4x4 cam 12-239-3 suggests 981-16 springs, but I can't find the specs on those. So will it float the valves with stock springs at 2500 RPM?
 
dyeager535 said:
Yeah, but whats the seat pressure on those stock springs? Something like 80 IIRC. My roller cam, which admittedly needs more seat pressure than flat tappet (but is still a very mild grind) *required* the use of better springs.

You say you are going to try it, but you need to check with the cam maker before you just slap it in. You are wasting time and money if you don't get the specs from the cam maker first.

For instance, the Comp Cams 4x4 cam 12-239-3 suggests 981-16 springs, but I can't find the specs on those. So will it float the valves with stock springs at 2500 RPM?
Click to expand...

comp cams said the cam will work with the stock vortecs ... it is everyone else on all other websites that say differently....

here is the cam
http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=08-411-8

now on the bottom of the page it does say...
Recommended Valve Springs 981-16

but it is not "REQUIRED"... to which they "WANT" you to buy more of their parts...

im not arguing with yall... just dont wanna do extra if I dont need to... so at least buy those springs.. but then what is required to put them in? any machining?...
 
Going off the top of my head, those springs are 1.25"(?) and that's the "standard" spring size. Which means machining to make them fit.

If the cam manufacturer says they will work, I guess I'd run it. Anyone can be wrong, but I'd be more inclined to trust the folks that make the products. You know they'd err on the side of conservative to keep from having warranty issues.

I'm kind of surprised the cam info doesn't actually mention the spring specs. I did a bit of searching, but didn't find any mention of that.
 
dyeager535 said:
that's the "standard" spring size. Which means machining to make them fit. .
Click to expand...

that is my point.. thanks for your reply... did you mean... standard size so no Need to machine??? just curious.... :crazy:


anyhow.. gonna get heads, intake and cam, bearings plus rings and gaskets...


mmm cant wait... gonna get heads first to make sure all is good :bow:
 
i had lunatti bracket master II

the 284 duration with .458 gross lift, not quite sure what went wrong but i wound up with a rod thru the oil pan and a rocker stud pulled 1/2" out of the head...i'm pretty sure it was due to over reving as it done this at about 6500 rpm while inching out of a mud hole...i had to have the heads machined for screw-in rockers..and put guide plates on also..i bought the same cam and two replacement piston and eagle h rods and then had it rebalanced and it will hold 6500rpm as long as i want to hold it there...i'm running domed forged trw piston that produce 11.25:1 compression and gm performance part intake #12464340...i can't find this casting # anywhere(it looks like #12366573 ) it has the bowties on each runner where it meets the head and the gm performance parts logo in front of carb???? , with a 2" phenolic spacer and a carter afb competion carb with the tall k&n tunnel ram air cleaner with the 5" element on the vortec's and comp cams magnum rollers because they are all measured at 1.52 ratio so no slight difference from one to the other and i absolutly love it...i also have a set of vortecs with casting #12558062 and a friend of mine has a set with #12558061 they all 3 have the three peaks cast on the end...are there any difference in these heads, why the different casting #'s?
 
No, that does mean machining would be required to run those springs. Vortecs use a smaller spring seat, thus why there are things like the expensive beehive springs, etc.
 
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