I was trying to help the OP avoid possible issues. It doesn't seem to me anyone that has responded is attempting to misrepresent anything or has an "agenda" of any kind. This is a forum. Constructive, informative, helpful discussion is why it exists. There is and has been no intention to belittle or argue with you in anyway on my part. Sorry if you are taking any of the conversation on here personally and I hope the post I'm responding to is not directed at me?

 

For what it's worth Mako, I don't think that was directed at you.

Pete

 

Don't some one make an inexpensive tool to mill down the guides some?

 

Yes! I pointed that out in post number 16 of this thread.
http://forums.corvetteforum.com/1586115428-post16.html

 

think summit sells them Im horrible with their search function 11/32 pilot

 

As much as I love afr heads, it doesn't sound like your shooting for shittons of power the vortecs should suite your purposes just fine. They make good power and torque. Bk has a vortec headed 383 and runs 12's and there definitely an improvement over the 882's. You plan on running it on the chassis dyno when it's all back together? When I did the l48 top end we gained 14 rwhp on the chassis dyno, but for the price of a dyno session up here you can buy an exhaust gas analyzer and probably pick up the same by properly tuning your air fuel. Good luck with your project.

 

Alright v2 after rereading the thread from start to finish I see I stole your idea. Your right, My bad bro. May the thought police smack my imaginary pee pee.

 

Check Post 7. I put a link up to an article that explains how to easily modify these at home with inexpensive tools readily available. They will make good power, capable of well over 400 HP with small ports. The flow might top out around .450 lift but all that means to me is you get optimum flow there so the more time you spend @ or above the more power you can make. A cam that lifts to .450 only reaches optimum flow for the time it is there, a couple degrees. These are fine for the OP as long as he does what he needs to. You can pull the studs and replace with screw ins easily also which I would do if running stronger springs with more lift. I pulled a couple studs on a 351 years ago and popped a couple lifters out of the bores in a 1/4 mile run. It was ugly. Lost oil pressure and wiped the crank bearings.

 

That's been my thought as well on peak flow at it's given lift. I would think that you could pull the studs with a socket, washer, nut, ratchet and socket. Then tap the hole for the thread Size on the bottom of the stud. Couldn't you also drill and pin the studs with a roll pin. Either of which an easy Sunday afternoon project to do that and mill down the guides some. If replacing with screw in studs couldn't you also run guide plates with the screw in studs? Billa is by far the master of the vortec in my mind. Wonder what his thoughts are on the diy mods. I know from his posts that he feels the studs were fine, but if he were going to modify them...

 

I pinned the studs on a set of Vortecs for a friend that didn't want to buy screw in studs and guide plates. It wasn't quite as much work as pulling them and tapping for screw in studs. You need to face off the top of the stud boss too. I've done that on my mill and on a head machine. It could be done with a hand drill and a piloted cutter.

 

What a surprise, here we are right back at doing machine work on a brand new set of heads out of the box. The thing that people said they absolutely, positively weren't saying.

I have never - ever - seen an OOB Vortec pull a stud. Period. If someone has, please call it out. There's no need to do anything here. If they're used heads that have been hot-tanked, then pressed studs should always be replaced with screw-in studs (shoulderless or shouldered w/guideplates as needed) as I've posted here many times.

Lifting well beyond peak flow on the Vortecs offers little power improvement, as the real gain is in the mid-range flow - this is key to understanding why huge cams and Vortecs are not really a great match. Sure, a bigger cam will make more power...if the heads are being used to their power potential, as in drag racing. For a street car, these differences are pretty minor. A higher ratio rocker will also make more power, as it increases the effective - but not actual - duration by moving the valves to full open faster. BUT...this also typically requires slightly opening the pushrod hole in the head...more machine work.

The spring's job is to allow the cam to reach it's RPM potential without float - the more aggressive the cam, the more aggressive the spring...and the more upgrades overall the valvetrain needs to be. Now...the stock Vortec spring is well under what's recommended for some roller-profile cams...but it's important to consider the RPM range of the cam, and how the car will be used. If it's a drag racer going to 6K RPM regularly...then you bought the wrong heads and the discussion is about the right heads...not how to make an apple into an orange

And again...last post on this thread: by the time you spend money for screw-in studs, guideplates, hardened pushrods for the guideplates, machining the valve boss, springs, retainers, aftermarket rockers, etc....you should have bought a better head. In this case, the OP just bought the wrong cam - he can send it back, get the right one, and be done with it.

I don't understand why these concepts are so tough to get across. Trying to make the Vortec into something it's not defeats the whole purpose of a budget head.

 

Like I said I figure your the king of the vortec head. It sounds like the op has already bought the cam and $150 would buy a new cam, but what would the tool cost? I know you oppose work on the head to make it work, but would you need to mill the guides down or mill the spring pocket to make the 268 work? I suppose the other cam could be sold to recoup some of the expense for the new cam. You say the studs won't come out and I believe you so the studs wouldn't need to pinned. If .450" lift is the safe lift then the even the xe262h is to large. The only thing I said about not machining was in reference.

 

Vortecs may not be the "best" heads, but they sure are a good bang for the buck.

One of the reasons I opted for cast vortec heads (price and horsepower gains being number 1 and 2) was strength.

Aluminum heads are absolutely fabulous, but I figured it couldn't hurt to put on some heavy duty cast heads that will do well in daily traffic.

My goal wasn't to build an all out race car, just bring the car to a decent standard of sports level.

Like the man said:

"effing run them"

 

Here is the dilemma. We are looking at budget. The vortec heads are bought. The upgrade springs are bought. The cam is bought. The intake is bought. The point of no return is reached and the OP has a plan. Now we have to figure out the most cost effective way to make these parts work as a unit. Telling him to "JUST F_ING RUN EM!" and "There's no need to do anything here" seems to be a poor option since the lift of .477/.480 is beyond the capability of these OOB according to Billa who has a lot of experience working with these. The stock vortec #80 spring pressure is not adequate for the cam according to the cam manufacturer. If it is me there is NO WAY I am running known incorrect spring pressure on ANY flat tappet cam. This is the only reason there has been any mention of doing some low cost, fairly simple, at home modification while the springs are off to make sure there are no problems with the known issues this combination of parts presents. The OP needs to be aware of and know his options up front. What is the most cost effective solution? If it is buying a new cam for $110 what cam works with the stock springs? Cutting the guides down on the bench at home and using the parts he already bought seems most cost effective to me. Instead of bickering the goal needs to be helping the OP reach a goal of a dependable, quality upgrade using what he has already dropped his money on and presenting him the options available to do that. IM OUT!

http://www.chevyhiperformance.com/te.../photo_02.html

 

I think 63Mako summed up the situation here pretty well. From my experience with Vortec heads, starting with screw in studs, upgraded springs, cut valve guide bosses and an xe262 cam (.469 lift with 1.5 rockers), and understanding that Vortec flow peaks at .450 lift, I did note ET and mph improvement when I switched to 1.6 rockers. Doing the math, exh valve lift was thereby increased to .500. I'm talking about 1 tenth sec reduction in ET, nothing you'd feel on the street, but significant to me. Then I switched to a hyd roller with about 6 deg additional duration and lift of .535 and .550, with 1.5 rockers. That resulted in an average ET reduction of another .2 sec and a full 1 mph improvement. I'm not trying to sell Vortec heads, but the OP has them already. My point is that even though their flow #s are not impressive at higher lifts, adding lift will improve power levels due to the "area under the curve" increase with the valve being in optimium flow range longer by passing that point and then coming back rather than just maxing out at peak flow lift.

 

I agree with Billla, in that the Vortec heads are a great deal in a certain application, but as soon as you start sinking any money into them, they become less and less of a great deal. However, as 63mako hass observed, we are dealing with a situation where the OP has kinda painted himself into a corner. He has purchased a cam that is beyond the capabilities of the heads that he has purchased. What to do? New cam? New heads? Modify the existing heads? The tool to modify the heads for increased lift is relatively cheap, around 50 bucks, I think, and if a set of Z28 springs would provide enough pressure, I think you can get them for around 25 bucks. Seems like this would be the cheapest way to go to make the already purchased cam and head combo work together. As far as the pressed-in studs, well...the cam and spring combo I just mentioned shouldn't be that rough on the studs...I'd roll the dice and leave them as-is.

In the interest of full disclosure, let me say that I don't have any actual experience with Vortec heads, and I am far from what anybody would call an engine-builder. (For example, I have no idea why hot-tanking would have any effect on pressed-in studs.) I am basically talking out of my butt. I know it, and now you do, too. So, take my comments for what they are...free advice with a double-your-money-back guarantee.

Scott

 

BK's findings are inline with what I have seen from Vortec heads on the flow bench. They do top out at .450" lift or so, heads and even port to port vary some. Although they don't gain much or any flow above .450", they don't start going turbulent and losing flow until somewhere around or .550". Lifting the valve over .450" but keeping it under .550" will give you more area under the curve letting the engine get better cylinder fill resulting in more power. The work the OP needs to do to install the cams and spring he already has on the Vortec heads he already has is not that difficult or expensive and is the best alternative to make what he has work.

Could the OP have come up with a better combination of parts for the money he spent, maybe. Is it a total mismatch and total loss, not at all. It should perform well if the rest of the build and tuning is done right.

 

We can always do better! Money and availability are always limiting factors for most of us.

I believe the OP has a great combination. His cam should handle the stock Vortec heads with no problems at all.

.48 lift on one side is not excessive, and not in the red zone of danger.

.45-.46 is the green (safe) zone, .47, .48 is the yellow, (caution zone) and .49, .5 is getting into the red (danger zone) of potential damage to the heads.

Your car will sound great and run like a scalded cat.

If you were worried about every single hundredth of a second for ET maybe you would want to do machine work.

Run em. And enjoy the feel of your head settling into the headrests

 

These springs are a drop in replacement and match the cam.
http://www.compperformancegroupstore...Category_Code=
There is still the issue of retainer to guide clearance. .050 Offset locks are available. This solves all the problems with no machining required but check all clearances before installing including rocker to retainer and retainer to seal.
Don't care what anyone says do not run the stock vortec springs with the comp XE268H cam. The differences are to great as shown below. Valve float sucks especially if it is way lower RPM than the potential of the cam.

Stock Vortec springs GM#10212811
#80 seat
#208 Open (.500 lift)
Rate 256 Lbs./Inch

Comp Spring 981 recommended for XE268H
# 105 seat
#290 open (.500 lift)
Rate 370 Lbs./inch

LS6 beehive GM PART # 12499224
Seat pressure @ (1.800 installed height) #90
Open pressure #295
Rate 372 Lbs./inch
Max lift .570

I would like to figure out a combo of either offset locks, retainer, shim to set these up @ 1.750 to get a seat pressure of #108 and still have .520 lift. These springs are about $50 for the set. Apparently these are able to be used as the thread below from another forum lays out.



You can also use the LS6 springs as described here:
http://www.thirdgen.org/techboard/te...ortec-lt4.html

"If you use the GM LS6 beehive valve springs (GM PART # 12499224), Comp Cams retainers 787-16, and change the umbrella valve seals to Sealed Power Part # ST2015, you should be able to get up to 0.550 lift. (I am currently only running .492 lift with this combination with no problems, however in the next couple months I will be swapping to 1.6 full roller rockers giving me a lift of .525.)"

 

Where do the green yellow red zone come from? reference? Everything I see says .420 to .460??? What "safety margin" are you assuming between the retainer and seal? Are you saying run springs that have #25 less on the seat, #82 less open pressure and #120 less rate than recommended by the cam manufacturer on a fast ramp hydraulic flat tappet cam with zero clearance at the retainer/seal interface? Again, I'm not saying junk the heads and start from scratch and not trying to argue with anyone. I been building engines for 40+ years. Some of my biggest lessons were also the most expensive. One thing I know for a fact is proper spring pressures and clearances in the valvetrain setup are critical for optimal performance and durability. A seemingly minor error or assumption can cost you a motor. Been there done that more often than I care to think about.