Good news. Save your money. The Vortec heads do well as cast, porting will not bring worthwhile inmpovements, IMHO. Search around Chevy Hot Rod forums, if you want better heads sell the Vortecs and buy some AFR Aluminum heads. I'm not sure what the factory valve job is on Vortecs, but if its not a 3 angle job, you could do that, polish the chambers and the exhaust ports and make slight improvements. Any machine shop should be able to do that for you.

Also, those motors had leaky intake manifolds. They make heavy duty replacements that wont warp and leak, a good idea if youre using those heads on a 350 Vortec motor.

 

ok maybe i wasnt clear about what I am doing. I have a set of vortec heads off a 97 chevy tahoe with a 350. I am going to put them on my gen I sbc. The problem is the stock valve springs, which is what the heads are now - stock, will not allow you to run a cam bigger then .420 or else the valves float.

I wasnt planning on porting or any fancy valve back cut. All i want to know is how much people have spent at a machine shop to have the heads machined for bigger valve spings and retainers.

I could buy a set of AFR or Trick flow sbc heads that would work great, but the vortecs are cheap and they flow great, actually they are just under the trick flow heads for power potential. It is easy to get 400hp out of a sbc with a set of vortecs and not spending a lot of money.

 

I thought it was .480 limit stock... and the issue is hitting the valve guides, not float. Any machine shop should be able to modify the heads to accept a little bit more lift. If youre running much over .500, I'd go for stronger valve springs and rockers as well. This is where Vortec heads start to lose their appeal, now you'll have more $ into the Vortecs than other comparable iron heads, and have to use a Vortec style intake manifold. Vortecs are great if youre running a milder cam, other heads are better for high lift applications.

 

I have read a lot of tech articles on the vortec head, just do a google search.

 

I have read just about every good tech article about vortecs on the internet. I know what they are capable of and how they stack up against other heads. In fact they flow better then almost all compareable, i.e. intake volume and exhaust volume, valve size, combustion chamber, etc., iron heads on the market.

I emailed the Summit racing tech line and the tech there suggessted no more then .420 of lift or else the valve will float, no contact.

I realize that bigger strong valves are in order, such as a 1.25 or 1.47 spring, but I really just want to know the amount of actual machine work that people have put into their vortec heads to make them work with a bigger cam.

I can get a set of modified vortecs to take a .525 cam from scoggin dickey for around $650, but i already have a set so I would like to go from there instead of starting again.

 

i agree with mountain 4x4. if im not mistaken it is a max of .480

im running a set of vortecs on my motor now. long story short - bought a new set from jegs , they said they would work with the comp 4x4 cam i bought. it was max lift of .480. well lets just say the press in studs didnt stay to pressed in. went round and round with jegs and they finally gave me my $$$ back.

i ended up buyin a set from summit that is already machined for up to .520 lift. i think theyre machined down a little, and they have screw in studs and they have worked good for the past year now. sorry i dont have a total on the $$ i spent but hey, thats all i got .

lata ryan

 

i had read .480 all over the internet too but when i asked summit they said .420 so I just took it from them as being the correct one, easy to be too conservative then over doing it i guess. I am guessing that the heads you bought from jegs were the stock ones??

I am not really sure but I think that selling the heads I have now and just buying a set of aftermarket ones from summit or the modified ones from scoggin dickey would be the easiest way and also less of a head ache.

 

There was an article in one of the "tech sections" of one of the hot rod type mags that said the original number of .420 was wrong and went on to explain. I believe the 480 is correct as well...

I looked this up once before...but forgot it...but...look at the part number for the springs on the vortec head and then notice that they are the same for the heads on cars with higher lift factory cams...

I ended up using a set of crane beehive springs for like an ls1 on my vortec heads....they have the smaller seat diameter...if that is the correct term...and you don't have to cut the heads for the bigger seats....

As others have mentioned...google a ton and read a bunch..

 

you wouldnt happen to have a part number would you?

 

this is what i was talkin about by machining the heads

http://chevyhiperformance.com/techarticles/148_0208_vort/

the inside of the valve seat is too big on the vortecs for aftermarket springs. Like they say its .900 where as most are .620 or something like that. I just looked on summit's website and the biggest they have with an outside spring seat of 1.25 is .870, just .30 off, but still a big difference.

 

Short Sub that is one cool looking rig!!

 

its funny you posted this because i was about to post something very similar.

i just threw several tools across my garage tonight after installing a comp cam 12-235-2 cam (.447/.462) in an older gen 1 block with vortec heads. i bent a pushrod torquing the rockerarms and found that i had spring bind/ bottom of the retainer touching the seal.

the .480 max lift is a bullshit myth, designed to ruin my weekend and cost me more money.:mad3:


here is what i found so far tonight.

1. sallee chevrolet has an article talking of crane cams part number 10308-1 (a spring and retainer kit) offering .550 lift without machining.
http://www.sallee-chevrolet.com/frame.html?/Cylinder_Heads/Vortec.html

2. comp cams and crane sells a tool to put on a half inch drill to mill down the seats. (i'll sell it to you cheap next week after i buy and use it.)
http://chevyhiperformance.com/techarticles/148_0208_vort/

3. custom classic trucks website has a tech article describing using pre 96' valves in an effort to use the older method of oil sealing ( a o ring and a tin umbrella) since the big seal vortec's use is the first thing to bind, claiming a .500 lift with no machining.
http://customclassictrucks.com/techarticles/0405cct_head/

as a side note, sallee chevrolet's website stated that the seals may not be pressed all the way in from the factory and you should check that too.

 

HAHA chevy hi performance said that there is a difference between the 062 casting and the 906 casting. But then Sallee says there is no difference. What to do?

I read on chevy hi performance website that the 906 has a modified seat that hurts low end lift numbers and those heads came on 3/4 and 1 tons. But i have two friends with 96 chevys pickups with the 350 vortec and both have the 906 casting. So I am guessing that chevy high performance is wrong.

At any rate thanks for the info. I was looking last night for about 2 hours to try and get some info on what I could do. Thanks for the help!!!

EDIT: Sallee just put the article on their website with edits made into by Sallee to tell readers what the actual truth is about them. So if you get a set of vortecs from say a 96 or 97 chevy truck with the casting number 906 then it will be the same as a set of 062 from the same years.

heres the website for the crane valve springs that require no machining to fit.
http://store.summitracing.com/defau...=0&y=0&searchinresults=false&Ntk=KeywordSearch&DDS=1&N=115&target=egnsearch.asp

sorry to hear that it didnt work out for you, why dont you just buy the spring kit and return what you can i guess

 

yeah, i am going to try and return them, but im betting i cant since ive been hording parts for 6 months for my build i finally did last night. not sure the crane spring rate is right for my application yet, either.

if i cant return, it will be cheaper to buy the machine part from comp and just mill them and go with an aftermarket seal. im betting the tool mills the seat down and uses the surface the current valve seal rides on as a guide.

want to buy the tool from me next week when im done? i have 16 seats to mill and then i will never use it again.

chevy high performance screwed the moose with their article about 906 vs 062 heads. the hardened seats can come on both or niether castings and must be researched though vin and sn numbers. they sure did drive up prices on 062 and make 906's cheap though. since the article, several reputable articles have been wrote busting the bad 906 rumor.

 

i would buy the tools to do it but i dont know when I can get around to it. My junk is in pieces in the driveway and I have more important things to worry with right now, like makeing it run. The heads were an after thought from a friend that wrecked his 97 tahoe and sold them to me real cheap.

I would like to go the easiest route and buy the crane cams springs. Although I dont know yet what cam I am going to run and those springs could be too much for a smaller cam. I think before I buy anything I am going to have to do a little more research and ask the summit tech guy again and spring rates vs. cam lift. If you still have them in a couple of months drop me a pm and I may be interested then when I got some time, money, and a running rig.

 

cool. i would get the crane springs sallee uses if i were you (if they are applicable.)

i did some mikeing today, and i think even if you solve the spring binding issue, the retainer to top of the seal is what actually touched first, with my springs (which are the ones comp said would work just fine, and they do not) binding not far behind. i wonder if sallee chevrolet changes the valve seal to a different type to say they get .550 with the crane kit. they have too.

i will let you know how it turns out machining it down, im ordering it tomorrow morning. if you want it after that, let me know, it will be probablly be sitting on a shelf in my garage for years after next week.

 

What the hell does lift have to do with float. Will your high lifts cause valve float on the bench? I am thinking you are mixing up float with high rpms. Anyways, some good reading: http://www.2quicknovas.com/vortecheads.html

 

weasel meant the springs, or the retainer to seal would bind, not float.

i bought the comp cams cutter to mill the seat down and cut the o.d.of the boss for the new springs today.

also got the cutter the mill the height of the boss down and change the o.d. for where the .530 aftermarket teflon seals fit

the way i understand it, both cutters fit an arbor that is run through the head and out the boss to line it up. should be easy to work as long as i pay attention to the mike.

i will update when i get it done this weekend.

 

anything to report yet? I am really interested to know now that I just found out the heads that I do have are infect with rust and the valves are almost shut:shaking:

O well I dont want to put money into crap heads anyway. Let me know how it goes, and give a price on the tools. I thought my current heads woudl have a longer sstay of execution.

 

machining the heads was a joke.:smokin: there were three tools involved. they cost around 90 bucks i think.

i measured the clearance i had stock, subtracted it from the size cam i have and added some fudgefactor. (and a bigger cam down the road)

the 3 tools and what they do:

1. an arbor that lines up the cutters, it rides inside the valve boss. the cutters slide on it and attach with a hex key. i used a big hitachi hand drill to turn the arbor.

2. the first cutter machines the OD of where the seal sits to 530 for the aftermarket seals (apparently most aftermarket seals are 530 teflon and vortecs are 560) and at the same time it cuts down the height of the boss so the bottom of the retainer and the top of the seal dont contact.

3. the second cutter cuts down the OD of the base of the boss to use aftermarket springs with dampeners(comp cams wanted me to remove the dampeners to get the springs to fit before, and i didn't like that), and at the same time machines the seats down for an increased lift cam without coilspring bind.

the cutters goes though the cast iron like cheesewiz, it wont take you long. just go slow and mike your work. i checked my work by assembling the valve in the head with the retainers and locks in place and no springs in. i raised the valve all they way up and took measurements off the bottom of the retainer to what i was cutting. i machined mine to accept .525 without trouble.

last but not least i used a dremel tool to clean up some thin sharp edges i made with the cutter when i machined down the seats.

 

There is no diff performance wise between the two different casting #'s on vortec heads. I have .600 lift springs on mine, I run the 97 matching roller block with a hydrualic roller at .510 .520 lift. I also run the comp cams narrow body roller rockers without guides, (I have guide plates). I had a valve job with new seals done also. The heads were decked also. I have not touched the chambers at all with a tool and my motor revs too 6000 in an instant. These in my opinoin are some great cast heads. As for the prices it will depend on the shop and location. I worked at a machine shop so I traded labor for the work. For the intake I used an rpm air-gap and used factory gaskets from the dealer and have zero leak problems.