vortec head question

[Guest Anonymous]

Hello, ive been doing a lot of research as to what heads to use on my 287 ci small block. Vortec heads for many reasons have come out victorious in comparison to many other heads out there.. The stats you read on them is up to .500" lift before needing to shorten the valveguides. 1.94/1.50 valves, great flow, make power up to 6000 rpms. now is this 6k power dropoff due to the fact that these heads mostly go on 350's so they run out of cam above 6k due to the .500 inch lift limitation? or is it because of some other factor? such as the rockers?? I figure .450" lift should be plenty adequate for almost 7k in such a small ci engine -like a 287... just for consideration im planning on using full roller rockers in this application. Thanks for any info regarding this rpm limitation DAN

[pparaska]

Dan, I think you're on the right track. The rpm available is a function of how much flow you need at a certain rpm, and a 287 would need 287/350 as much flow at the same rpm.

 

I do think that you're going to need screw in studs, and maybe even a stud girdle, becuase the cam you're going to be running in a high rev'er like that is going to require some hefty springs.

[Tim240z]

Dan,

If you drop a few bucks more on the heads, you can get the upgraded valve train from the factory, which gives you up to .525 of lift. Well worth the minor extra expense.

Tim

[grumpyvette]

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

 

I just went through this for the 10 zilionth time replaceing springs and machineing the guides so I could install a .545 lift cam on a hydrolic lifter, vortec head 383 for someone, so you guys might also use the info

there are several things that effect the max lift your heads/springs/retainers can handle other than (spring bind) look at the diagram here. http://www.cranecams.com/master/vsprings.htm

.read this

http://www.hotrodheaven.com/comments/messages/9058.html

 

now with cheap springs its usually the spring coils stacking up and (binding) that limits the amount the valve can be opened but the bottom of the retainer hitting the top of the valve seals/valve guide comes in as a close second in the race to cause clearance problems so you must check that too! just adding the better springs that are normally rated at either .540, .575, .600 will give you more clearance but in most cases Ive measured the retainer /seal clearance will limit you to about .500-.510 if your just changeing the springs, and yes it is possiable to gain some clearance by useing special .050 higher notch valve locks that move the ratainers alittle higher on the valve stem but if you want to do it correctly and don,t have the measureing equip. just take the heads down to your local high performance cylinder head rebuilder and have him machine the valve guides for the .600 lift clearance and have him use these valve seal,(Hi-Performance Teflon Seals) (Machining Required) read this http://www.cranecams.com/master/vmisc.htm

and this http://www.babcox.com/editorial/ar/ar79842.htm

 

http://www.sallee-chevrolet.com/Fast_Burn_Cylinder_Heads.html

 

IM not knocking the vortecs performance they are some of the best cast iron heads chevy makes Im just saying your money can get you more head per dollar spent elseware.

vortecs are great heads for building torque and hp in the 2500rpm-5000rpm range useing cams with about .460 lift max(big surprise, they are truck heads designed for max torque/hp in that rpm range) now lets look at the costs versus power available, if your going to use them (as is) you have about $450 in heads and $175 in an intake or $625 to run the heads correct? oh wait you forgot the guide plates or the self aligning rockers $50-150 more if non roller rockers are use so your up to $675 minimum and dont forget another $100 or so for changeing to screw in rocker studs if your going to run that engine hard,oh wait if your going to run that engine hard you will really benefit from a larger lift cam so thats another $80-175 to get better springs and the valve guides cut down to allow a .550 lift cam to make this car fly, so were up to about $800- $900 with the pocket port job ,even if you do that yourself.now do you see why the other aftermarket heads that flow more and include the other stuff and run stock type intakes are a better deal!heres a few good deals (depends on what your looking for)but keep in mind its the TOTAL COST not the initial cost and the TOTAL HP POTENTIAL that matters

http://www.midwestmotorsportsinc.com/mms.nsf/pages/Specials (look at the IRON EAGLE HEADS)

http://www.jegs.com/cgi-bin....enbr=76

 

http://www.flatlanderracing.com/index.html

 

http://www.canfieldheads.com/sbc_2600.html

 

http://www.trickflow.com/product/prhomefeature_index.htm

 

after looking at all the options.. there are better choices but do your RESEARCH BEFORE BUYING PARTS AS TO WHAT WILL AND WHAT WONT WORK!!

[Ray]

Hey grumpyvette what kind of tooling are you using to do the vortec heads?? I have heard there is a cutter and pilot combo out there made just for the vortec heads....I paid a friend to do mine in a head machine but was wondering for my next motor.

[Guest Anonymous]

Thanks everyone, especially all the links, but i think what im trying to say is because of my small displacement engine 287 ci im not gonna need a lot of cam .450 or so should be plenty, the vortec ads always say power to 6000, with an assumed .450" lift on a 350ci engine. well as pete noted my engine has a lot less cylinder to fill per intake stroke, so im asking will this smaller engine allow these same heads to rev higher with the .450" cam due to its smaller displacement thanks, DAN

[grumpyvette]

heres where you buy those basic tools

http://www.goodson.com

heres part #

s-350g....sp-600....chr-16....vsc-500343...vsp-823...vss-1500....vp-343....mvs-130