Has any one here put Chevy vortec heads on a 283/327? How much better/cheaper are they than the camel humps, etc. heads? Is compression reasonable? I know a new intake and bolts are needed, just have never seen this done. Also, what is a good head for a small blck 400 chev? What cc combustion chambers do I need to run regular gas? any info is appreciated. Thanks.
Not many people know it but when Chevy came out with the Vortec heads in 96 they were made for 4 different engines used in pickup trucks: the L35 Vortec 4.3 liter V6, the L30 Vortec for 5.0 liter (305) ,the L31 Vortec 5.7 liter (350), and the L29 Vortec for the 7.4 liter (454) big block. Each engine for 96 had a substantial horsepower boost over their 95 truck versions. If I am not mistaken the L30 305 heads have 56cc chambers and should work well on the 283-327 blocks while maintaining a streetable compression ratio. The valves are smaller but they have excellent low-lift flow which accounts for some of the increased torque and horsepower in the 96 engines. Early versions did not have the three angle valve jobs so you might want to look into that. On the negative side if you go to a salvage yard to find a pair there are reports that they are not as durable. My memory is a little fuzzy but I think it's because the cast iron in them was more prone to cracking. If on the other hand you go with the L31 head from the 350 you will be facing lower compression issues and how to overcome that by milling etc. I believe the L31's have 64 cc chambers. Good luck.
you were indeed. 96 was the first year for the vortec v8 heads. i cc'd all the chambers in my gm performance parts L31 heads between 61.8-62.4 cc's compression all depends on your pistons, head gasket thickness. without knowing that it's a crapshoot.
the Vortec head wasnt avalable on a 350 until 1996. The 305 vortec head is not nearly as good performance wise. It lacks the good combustion chamber that helps make the Vortec head rock so well. GM used the Vortec name for several years before 1996 but only on 6 cylinder truck motors. The 350 vortec heads are pretty much a clone of the late model LT1 aluminum heads except they are made of cast iron and have conventional coolant flow instead of the reverse flow that the LT1 motors had ( not to be confused with the 1970 LT-1 motors. Yes you were fibbed to because your truck is 5 years too old to have come with Vortec heads. Performance wise, the 350 Vortec heads will make 30 or 40 hp more than any camel hump head on the same motor. They are a huge improvement. They flow like an entry level race head does. a little over 500 buys a brand new set from GM. An easy way to tell a Vortec head is that it only uses 4 intake bolts per side and they go in straight down rather than an angle like a regular sbc head did. The better chamber in the Vortec heads will let you run more compression than you could get away with on the old style heads. I ran them on my old 406 small block at 11.3 to 1 compression on sunoco 94 premeum gas. A 350 and flat tops would work out to be about 9.8 or so compression and if you built it right ( zero deck the block, ect) would work good on regular or for sure on midgrade gas. Doug yes, I like Vortec heads. :' )
We had 25 96-97 5.7L vortecs in our fleet at work. They would crack at least 1 head everytime they were overheated. If the truck never got overheated you could just about set your watch to the fact that at least one head would crack at 150k miles. Keep in mind that all of these trucks were 3/4 and 1 tons that were used-up/abused in the hands of roofers. If you are buying used heads make sure that you check them closely for cracks.
the factory vortec intake gaskets DID fail on a regular basis. they were the hard plastic type with a neoprene rubber gasket molded in somehow and those pretty much all leak internally or externally sooner or later . Ive been lucky Ive had 4 or 5 sets all used and all still good no cracks.
-I'm currently building up a replacement 350 for my 3/4 ton that has over 220,000 miles. I'll be sure to source a set of Vortec's for the new engine. -Thanks!
Gearjam, You will also have to get an intake that will accept the Vortec vertical bolt configuration. I think Edelbrock makes a universal style that accepts both. Salee Chevrolet has a discussion board with a section devoted exclusively to Vortec head conversions for your small block Sallee Chevrolet Discussion Board: Vortec Head Questions Also Scoggin Dickey's parts Dept has extensive tech info and offers upgraded Vortec stuff in addition to the stock stuff. SDPC Vortec Cylinder Heads and Head Kits
-Excellent! I was looking at running an Edelbrock intake anyway. Thanks for the tips on the sites. I'll do my research!
So are you saying that roofers are hard on things that are not thiers!??! LOL! I am a roofer too! LOL! So, I know what ya mean! Vortecs are great heads. I have had a few sets since about early 97. I have not had a lick of trouble out of them. Got the first set from SD Chevrolet just as soon as Edlebrock came out with an intake. Nobody told me about needing self aligning rocker arms though. So on the Hot Rod Power Tour I bent every pushrod and broke 2. SUCK! Now I have them boosted on the Camaro and have had great luck with no problems. They like a little more timing than traditional heads also, or at least in my combination.
Find a copy of "Small Block Chevy Engine Buildups" by HP Books.....ISBN # 1-55788-400-5 They built a 422 hp (dyno'ed) vortec head equipped 350 ci motor using fairly inexpensive GM Performance parts. Scoggin-Dickey has new vortec heads for about $500 to 600 a pair, complete.
The Vortec castings were als0 revised in 98+. The newer casting is more durable and rumored to have a slightly better flow. I picked up a 99 truck motor right out of the shop with 10.5 pistons. I can't wait to put a 2x4 manifold on it. Chevy used the LT1 chamber design in the Gen I head casting when they came up with the Vortec. By all accounts, it is the best performing production head Chevy ever produced. RHS sells them with new and old manifold patterns and drilled for center bolt valve covers or early valve covers. I think they are about $600 or so with screw in studs and modified for high lift cams. The biggest down side is that a stock Vortec head is limited to something like .420 lift. You need to cut down the guides and install bee hive springs to get them up to about .550 lift.
I have vortecs on my Chevelle motor. I have the before mentioned upgrades with the cut seats and better springs for .550 lift. No problems here, and I would use them again. Can't beat the price/performance that they give you. As was mentioned, you need a special intake. The port spacing and bolts are unique to vortec heads. I have an edelbrock performer RPM intake on mine. You also need self-alligning rocker arms, and centerbolt valve covers. Rockers off any LT1/vortec motor work. You can use stock pushrods.
My personal opinion is there are better deals. I buy the Iron Eagles at $750 a set ready to run with good springs ,your choice of runner size. Plus I have a choice of about 7 million used intakes out there for 20% of new. I have used three sets of these,still have two and never had a problem.
I saw the Iron Eagles, I wonder how they stack up performance wise against the Vortecs? I was thinking in the near future of going with either one or the other. Anyone have any experience in it? Dart? GM?
Do a search on Chevy High Performance website for info about the performance of them. They did an article dyno'ing a bunch of different SBC heads along with the flow and such. Good info if you ask me.
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