Could you please post your cam specs and whether or not you've had any valve train problems. I'm thinking of going Vortec myself but my cam is 214/224 duration 480/480 lift, and supposedly this is too much (450 is the recommended max lift for these heads.) I wanted some 'real world' opinions from people who were actually running them with comparable cams.

 

my cam has .469 lift on the exhaust. I've been running this cam for a few thousand so far with no probs.
I shift at 5700-5900 when racing.

some say the stock spings are good until .5 others say .45 is their limit...

 

Running .462/.469 on mine, same cam as Jer. No probs for over a year.

Although I don't seem to be making as much power as I think I should, starting to wonder if I've worn them out and am losing some power up top or something.....

With the max lift on the Vortecs it's not so much how much will the springs handle that matters, but when will you get interference between the retainers and the valve guide boss stuff. General accepted absolute max is .480ish, I've known several people around here that ran .477/.480 with no problem but it's right on the borderline. Might want to check your particular set, production variances could make all the difference between having a problem and it working great for you...

 

I am running H-11 springs, and offset locks. The cam is listed in my sig. After I found 4 broken rocker arms, and got my aluminum replacements, I have had no problems.

 

I have a GM HOT cam in my 350 with vortec heads-.525 lift on ex and intake. I bought the cam and kit from GM. Installed the springs and retainers that came with the kit-machined .030 off of the bottom of the retainers. Pressed the valve seal farther down until there was .050" clearance when valve is at full lift. I have about 5000 miles on this setup with stock heads and no machine work other than the retainers-you could do them on a grinder. Runs great.

 

.487 / .490 lift cam.
maybe a 1,000 miles or so, no problem.
I did change the springs.

 

thanks for the info. Those of you who changed springs, what springs did you use, and did you have to bore out the spring pockets so that larger ones would fit? What are the largest springs I can run without having them milled?

James

 

I'm running the stock 330ho motor springs and flat tap cam. The specs are something like 212/222 and .435/.460 nothing special.
From the TBI board, it's been said that the Lt4 springs can be used for higher lift, not sure on the details because I haven't the time nore money to do a cam swap until this summer.
Do a search for Lt4 valve springs, suposedly they are the smaller diameter and just fall right in without any machine work.

 

I think the HOT cam kit includes the LT4 springs and retainers which is what I installed without any machining. Most of the car magazines say .480 max lift without any mods to the heads using stock springs.

 

The H-11 springs that I used are good to .600 lift. I am under the impression that these are more of a "cheater", or "claimer" spring, so they will be changed soon to some K-Motion H-11 springs. I trust them more, and the pressure is a lot better than what I have before I even used them.

 

running a .480/.480 lift cam and no problems as of yet

never brought it much past 5000, but this year its gonna see 5800 for sure


fingers crossed

 

One more thing. I pinned the studs with (I think) 5/64" roll pins to prevent stud pullout.

 

how'd you go about "pinning the studs"

im not quite sure where you'd pin them to prevent them from pulling, your talking about the stock press ins right?
I'd like to do something like what your talking about, just not to sure how to go about it

 

Buy a handful of 5/64" cobalt titanium bits and get the bare head over to the drill press and drill through the cast iron-thru the stock rocker stud and thru the cast iron-the hole goes right thru the stud at 90 degrees. Buy 16 5/64" roll pins at a hardware store and hammer them into the holes you made. Thats it.

 

The LT4 springs didn't require you to open up the spring seat size any? If not then that would seem to be the ticket for sure. I had thought they wouldn't fit...

 

I did not do any machining.

 

I just ordered some Vortec heads from Pace yesterday. The guy told me .488 was the max on those heads. I have a 480 lift on my cam. It's cutting it close and I shift at 6000+ We'll see how the hold up at the track.

Brad...

 

Well just picked mine up from the machine shop yesterday...

Were stock now:

Comp cams springs 981's, locks, retainers from the K cam kit with an XE268 (477/480 lift)

Milled vavle guidebosses for higher lift, he checked they would NOT have cleared on my set of stockers, and ARP screw in studs..

total machinng costs $98 so I am still cheaper than "aftermarket" heads...

using GM stamped self aligning rockers, (suggested on THIS board), and throwing them on a 383 It will be done soon I'll let you know how it is

 

How much did they mill the bosses?

Mark

 

WOW old post but in case anyone is still wondering

the vavle bosses were milled about two hundred thousands

 

Face it, anything more than .450" lift and you'll have to
modify the heads. By what ever means.
Any reputable automotive machine shop can do this
routine job for a fair price.
Any thing worth doing is worth doing right.
Any unreputable shop can do it wrong and overcharge ya.
Even with new springs ,guides machined and screw in studs and guideplates installed, you'll still have less money in 'em them aftermarket heads.

Got a .480" lift street roller and vortecs, you're going to need a better than stock spring and some guide clearance attention.

They're beauti street and strip heads.... good luck.

 

I just put the Vortec heads on my car. I had screw in studs, guide plates and valve guides machined down K-Motion K-700 springs. $160 + parts. I'm good to .500 lift.
I'm running the XE268H cam with the Edelbrock Performer Vortec intake and 800 cfm carb. I love it. Car really gets up and goes. I just passed emissions today with this setup. Now I can cut off my exhaust and put duals on. I couldn't believe I passed. YES!

Brad...

 

My car flew thru the emissions too. GM did their homework on these heads. There is more rocket science there than meets the eye.