vortec vs double hump heads - Chevy Nova Forum
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Old 23rd-November-2009, 09:18 PM   #1
ky66ss
 
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vortec vs double hump heads

im wanting some opinions on cylinder heads ...im building a new motor and have 2 sets of heads here and trying to figure out which way to go...first off the motor is a late model 1 piece rear seal 4bolt 350 new 10.1 pistons (with 64cc heads) edelbrock roller cam 539/548 lift 234/238 dur. @0.50 . the first set of heads is a fresh set of 1969 186 casting double hump with 2.02 1.6 valves screw in studs and guide plates....and then ive got a set of vortec heads im confused about they are new complete 906 castings and from what im reading the dont perform like the other vortec heads...the are stock and are gonna have to have some machine work and springs....whats your opinion? thanks in advance for your help....also looking for a oil pan for late model block for first gen. nova...
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Old 23rd-November-2009, 10:00 PM   #2
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Originally Posted by ky66ss View Post
im wanting some opinions on cylinder heads ...im building a new motor and have 2 sets of heads here and trying to figure out which way to go...first off the motor is a late model 1 piece rear seal 4bolt 350 new 10.1 pistons (with 64cc heads) edelbrock roller cam 539/548 lift 234/238 dur. @0.50 . the first set of heads is a fresh set of 1969 186 casting double hump with 2.02 1.6 valves screw in studs and guide plates....and then ive got a set of vortec heads im confused about they are new complete 906 castings and from what im reading the dont perform like the other vortec heads...the are stock and are gonna have to have some machine work and springs....whats your opinion? thanks in advance for your help....also looking for a oil pan for late model block for first gen. nova...
Not sure if 906 is the ones I'm thinking of but the very early Vortechs had a ramp inside the intake port pocket to create a swirl effect past the head of the intake valve. If those are what you have they are good for low to mid range torque. The best High output vortechs don't have that intake port pocket ramp.
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Old 24th-November-2009, 08:50 AM   #3
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The 906 and the 062 Vortecs are good but the 062 Mexican Vortecs have smaller intake runners.
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Old 24th-November-2009, 03:41 PM   #4
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The Vortec's will need some work and quite possibly longer valves in order to accommodate your higher lift cam...That being said, they should easily out perform the old double-humps.
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Old 24th-November-2009, 09:29 PM   #5
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Sorry to jump on this thread, but when Scoggin Dickey does their vortec head mods, what exactly do they do? They say it increases the lift to .525" but is there anything else they do?

Thanks

Dave
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Old 24th-November-2009, 09:46 PM   #6
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No long valve or anything special needs when you modify a Vortec head for lift past the .480 mark.
Most will work just fine to .500 lift. (from what i have seen)

All you need is a cutter to lower the valve seal.
IE: http://www.goodson.com/store/templat...l.php?IID=7407

You remove the valves & valve springs.
Cut the top of the valve guide down and install valve seals.
By cutting the valve guide down you increase clearance between the valve seal/guide and the valve spring retainer.

Illustration "B" is the area that needs more clearance.



I do this and charge 75.00 plus price of seals. I also check valve seat angles and lap the valves in.

.
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Old 25th-November-2009, 01:38 PM   #7
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Hey Al,

Where did that pic come from? It seems to be the best cut section of the valve train that I have seen.
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Old 25th-November-2009, 01:57 PM   #8
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Hey Al,

Where did that pic come from? It seems to be the best cut section of the valve train that I have seen.
Old crane catolog
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