vortec question
Thread Starter
Racer
Joined: Jun 2001
Posts: 440
Likes: 0
From: Sanford Florida
vortec question
I know with new centerbolt style heads, i need a different intake, but my machinist and i have aggreed that we can change the bolt holes easy enough. Is there any other difference between the two manifolds? I can get older style manifolds for much cheaper, and even with the slight machining costs (a 12 pack :cheers: :) ) they will still be cheaper. Are there other differences?
Melting Slicks
Joined: Mar 2001
Posts: 3,365
Likes: 5
From: Lake Villa IL
Cruise-In IV Veteran
Cruise-In V Veteran
St. Jude Contributor
Re: vortec question (chuckb01)
I just read that GM makes Vortecs that are compatible with the older style manifolds as well. I haven't verified this, but it's a thought.
Pro
Joined: Mar 2002
Posts: 511
Likes: 0
From: St. Louis MO
Re: vortec question (chuckb01)
I have modified a Preformer manifold for the centerbolt heads. All you have to do is grind out the middle four holes so that the bolt hole is pointed almost straight up. I then machined a flat spot on the top side to give a better clamping area.
The vortecs are a little differnt. They only have the outer 8 bolts. And they are straight up. So to do this you will need to drill through the intake at the right spot then make a spacer that is angeled on one end so that the bolt will apply even pressure to the intake. That should do it. Make sure that you get a good seal in the middle, you could have your machine shop drill in the middle four holes for you while they are fixing up the intake and you would even get a better seal than the standard vortec intake.
The vortecs are a little differnt. They only have the outer 8 bolts. And they are straight up. So to do this you will need to drill through the intake at the right spot then make a spacer that is angeled on one end so that the bolt will apply even pressure to the intake. That should do it. Make sure that you get a good seal in the middle, you could have your machine shop drill in the middle four holes for you while they are fixing up the intake and you would even get a better seal than the standard vortec intake.
Burning Brakes
Joined: Dec 2000
Posts: 1,183
Likes: 2
From: Des Moines Iowa
Re: vortec question (chuckb01)
Chuckbo1:
While you CAN drill and tap the Vortecs to fit the older style intake, this is NOT recommended by most, since the 'fit' that you will get matching the intake head ports to manifold ports, is marginal at best and you may have difficulty in obtaining and keeping an adequate seal.
Peforming the modifications you are considering to the Vortec heads was a popular thought a couple of years ago, but since many have experienced the sealing problems, and since there now are a number of aftermarket intakes available for this specific application, believe the best course is to purchase the new specific fit intake.
While you CAN drill and tap the Vortecs to fit the older style intake, this is NOT recommended by most, since the 'fit' that you will get matching the intake head ports to manifold ports, is marginal at best and you may have difficulty in obtaining and keeping an adequate seal.
Peforming the modifications you are considering to the Vortec heads was a popular thought a couple of years ago, but since many have experienced the sealing problems, and since there now are a number of aftermarket intakes available for this specific application, believe the best course is to purchase the new specific fit intake.
Le Mans Master
Joined: Aug 2000
Posts: 9,662
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From: Semper ubi, sub ubi
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Re: vortec question (chuckb01)
Chuckbo, John is 100% correct, you can get Vortec heads tapped to use the older style manifolds, but there isn't enough sealing surface for them to get a good fit. The ports won't match very good either. Edelbrock makes at least 3 different manifolds for the Vortec heads. The Performer, Performer RPM and Victor Jr. They might even have an Performer Air Gap, I vaguely remember seeing something about it. GM also sells their own version of the manifolds, along with TBI and TPI versions.
If you are going to use Vortec heads, use the correct manifold and GM intake gaskets. The GM intake gaskets are reusable and will make sure that you get a good seal.
If you are going to use Vortec heads, use the correct manifold and GM intake gaskets. The GM intake gaskets are reusable and will make sure that you get a good seal.
Intermediate
Joined: Jan 2002
Posts: 37
Likes: 0
From: Bloomington IL
Re: vortec question (tsw71)
If TSW71's picture doesn't make up your mind for you, I don't know what would. Aftermarket and factories design things for a reason, because they work. Any modifications to mismatched parts will almost always leave you wishing you had done it the right way. Voice of experience.
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Thread Starter
Racer
Joined: Jun 2001
Posts: 440
Likes: 0
From: Sanford Florida
Re: vortec question (ACLR810)
Thanks for the responses. I had heard from someone whos knowlege was qeustionable on the matter, so i verified it here. Between the pic and the posts, i can easily see that i should buy a manifold designed for the heads i have. you guys are great. :)