And vice versa? So if an unknown engine is fitted with center bolt valve cover heads, that would mean it has Vortec heads? Or is that too simple an explanation and there is more to it than that. And Vortec heads can be installed on earlier blocks, but require a different intake manifold, right? What about exhaust manifolds? Sorry if this shows my ignorance, I'll admit my weakness when it comes to the later engines.
Vortec? Do you mean the late 90s Vortec heads, that everyone wants? or the heads on an earlier Vortec engine, which no one seems to realize were also called Vortec by Chevy? But no, the center bolt valve covers started in 1987, long before they fixed the head design. Look for vertical intake manifold bolts, that's the giveaway that it has good heads
Center bolt does not always mean it is a Vortec head. You are correct on the intake and yes, exhaust manifolds interchange. Now I have a question. Can Vortec heads be redrilled to accept early intake manifolds or are the ports too tall, or different in some way?
Haha, yeah, thanks for the info Jim, always appreciate it. I do mean the 90's heads everyone wants. Now I'll go back and fix teh speeling, haha!
Thanks, so are the non-Vortec center bolt heads a later design, earlier design, or concurrent with the Vortec heads but without the same features? Again, sorry about my ignorance, but hopefully I can get a better grasp. I think if I have these questions, somebody else probably does too.
Vortec is a Chevy brand name, and it was (and still is? or did they finally quit?) used for many Chevy Truck engines, and only one specific one is the engine you are talking about. The specific engine that hot rodding folks refer to as "the" Vortec, is the 1996-2003 350 with the vertical intake manifold bolts. As I said earlier, the center bolt valve covers were introduced in 1987 on small block V8 engines, and the Vortec name was first used on the 4.3 V6 in 1985.
The non Vortec CB VC heads will look almost the same as any SBC head, except for the CB VC's. Unless the intake was changed on a Vortec headed SBC, it'll be made of some composite material...and looks nothing like a Carbed SBC intake. Also, there's only 4 or 6 bolts that hold the intake down on a Vortec headed engine-just 2 or 3 per head. I guess re-drilling the heads might be possible, but the intake ports are much taller than "regular" SBC heads...if it'd be possible, material would have to be added to the intake to get a seal.
Jim, can the early intakes be adapted to the Vortec head for a more traditional look or are the ports too different? I see that Budget36 has answered my question. Thanks.
I don't know, I've never messed with them. I think the issue is that there is no metal in the heads where you'd have to drill the holes for the earlier intake to bolt on.
I have read that some people are successful in reaming the holes in the intake to get the holes to align. I can't say for sure that works. Scoggins-Dickey does make an intake manifold that will work with a carburetor and Vortec heads but it looks like an aftermarket intake.
I believe that works on the early center bolt non-Vortec heads. The bolt pattern for the Vortec-specific intake is different.
I have taken a standard SBC intake and elongated the two center holes to fit 1987 to 1995 center bolt heads. It works, but it is not perfect if you are a perfectionist. There is no way to modify a standard intake to fit the vortec 1996-2000 heads.
It's confusing this "Vortec" thing! GM used the term Vortec on their TRUCK six, small, and big block Chevrolet engines. THAT "name" had NOTHING to do with the HEADS used; it had everything to do with being used in trucks. The ONLY two things that ID's a Vortec head, as used for the SBC for performance, is the last three numbers of the casting numbers, 906 or 062; both are crack prone however. The only other way is the "heart shaped" combustion chambers. Center bolt valve covers don't ID a Vortec head either, although they do use center bolt valve covers. Aftermarket heads of the Vortec DESIGN are better than the factory heads. The term Vortec had nothing to do with the short block. VORTEC, used as in the whirling motion of air inside the combustion chamber to facilitate the intake and exhaust of air. At least that's how I've learned it, and I could possibly be wrong; but I'm not, in this case, at this time, and in this place. I am Butch/56sedandelivery. The nephew and I used a set of the so-called "swirl port heads" on the mild 350 we built for the 51 Bus Coupe. At the time, the center bolt valve covers were also the "way" to ID Vortec heads. I was wrong then! But, those heads, despite what everyone said, "won't rev above 4500 RPM", easily revved to 6500 RPM (???). Some of the aftermarket Vortecs could use either pattern intake manifolds, and either pattern valve covers.
my wife has bought a few "late model" trucks, 1999 through 2012 models, they all say Vortec on the engine, plain as day, and none of them have a 350 engine.
Jim I thought 1996 Vortec head didn't have the have the center 2 bolts at all and lacked the exhaust crossover. The heads I call TPI heads did have the 2 center bolts at a different angle but didn't offer a preformance gain.
Correct^, no center intake bolts on the good Vortec heads, and the four bolts per head are perpendicular to the horizon. The original SBC heads used six bolts per head and those bolts are perpendicular to the intake face of the head. The later TBI heads have the two center bolts inclined on a 72* angle, but you can elongate the holes in the intake and use wedges ( from Summit, etc.) on older intake manifolds or use a new intake machined for the TBI heads. And there is a reason GM went to smaller diameter intake bolts on the Vortec head. Follow the correct torque pattern and specs, the wedging action of the straight up and down bolts makes them susceptible to cracking the intake.
It seems a lot of TBI heads get called vortec too. When shopping the easiest way to tell by eye is the angle of the intake bolts and absence of holes in the middle of the intake.
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