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Author Topic:   GM Heads question
No Shame
Dirt Newbie

Total posts: 4
posted December 10, 2001 12:34 AM
I need an opinion on vortec heads?
Are these things good, are they a better performer than the 461x head?
If i put the 202 valves to them and angle mill em and do it all.
Which is better?
I won alot of races last year with a 462 head with a hellish valve job.
Some people tell me that 461x are the best and others say Vortec.
Another guy at the motor builders run the vortecs last year and made hellish power, but he said he didnt like them because he felt as though they run out of working at like 6000 rpm.
Give me the scoop if you got it

sdhnc29
Dirt Freak

Total posts: 467
posted December 10, 2001 12:53 AM
Yes the Vortec heads are great !! By going to a 2.02/1.60 valve combination , your air flow increases dramatically ! On my flow bench , by going to the 2.02/1.60 and blending the pocket area , you pick up almost 100hp(potential) worth of air !! But don't go to a 2.055" intake , unless you are willing to un-shroud the chamber and gain some CC's . As far as angle milling , we generally roll these heads over .080" , and then take an additional .015" off after they clean up . Then we re-correct the intake and exhaust faces , and spot face the head bolt holes . I've seen these heads milled much farther by other engine builders , but they usually have a big problem with head gaskets ! The deck on the Vortec head is very thin , so you are limited to how much you can mill them , and still retain enough thickness to hold a head gasket . As far as over all compression ratio , you can cut the 461's much farther . But in my opinion , the large difference in air flow that you get with the Vortec's , well out weighs the 1/2 point loss in compression ratio ! Hope this helps !!

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

hughes
Dirt Maniac

Total posts: 141
posted December 10, 2001 10:06 AM
Hey sdhnc29, when racing with the Vortec heads in the classes where you can't port/ polish, is cleaning up the bowls/ casting lines worth the time. I also heard that you can cut the idle ridges out for around 20 H.P. I was also considering opening up the exhaust. But on the other hand you hear that with Vortec heads you can only ***** them up. What kind of work do you think would be good for Vortecs in the classes that aren't wide open on the Porting. I've alot of good/ knowledgeable replies from you and would like an opinion from you.

sdhnc29
Dirt Freak

Total posts: 467
posted December 10, 2001 09:43 PM
Hey hughes , thanks for the compliment !

Yes , going to 2.02"/1.60 valves and blending the bowl area is definitely worth your time !! As I said in my previous post , there is about 100hp worth of air flow in the larger valves and opening the bowls up . As for the intake and exhaust ports , there is only very little that can be improved on . GM actually did there home work when they designed this head !!!

In a class where you are limited to absolutely no port work /polishing/ or bowl jobs , then you can still go to the larger valve and gain ! Though the gains are not nearly as great , it would still be worth going to the larger valve . Usually in classes like this , rules are written in a way that you can do whatever you want with the valve job , just no port work . If this is the case , then I'd suggest finding a machine shop with a NEWEN (CNC) seat and guide machine . With this machine (the same one I use) , you can go into the pocket area with several different cut's , and achieve a pocket that is almost as good as a hand blended pocket !! The only area that actually suffers a little in the bowl , is the short side radius . But you can still gain a ton of air over the stock 1.94/1.5 valve's if you do this ! This should be done to both the intake and exhaust pockets !

As for the exhaust ports , they seam to be very good as cast . If your rules allow porting , then you will want to do most of your work around the guide area .

If there is anything that I've missed , just PM me , and I'll be happy to go into further detail , and answer your questions .

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