i'm wanting to switch to vortec head for a 88 350 tpi motor that i have. i noticed 2 different castings for the vortec heads, 906 and 062. which is better? is there any difference in them? i have the 062 castings off a 98 chevy k1500 350 motor. thanks for any info. tom

Like you said vortec heads came with 2 casting #'s. the better of the 2 are the 906 casting heads because they have like 20% better flow over the 062 heads. 062 heads come of the 3/4 ton trucks. So you have the lower flowing vortec head but hey man be happy you have vortec heads man those heads work wonders. But all in all 062 is less flow and 906 is high flow. Now remember if you bolt on those heads your goin to need the special intake base to be compatable with the vortec heads. SDPC sells them for around $400 hope that anwsers your question.

Jason

yes, thanks for the help. the 062 heads came off my uncles 98 1/2 ton 4x4. thanks again, tom

No Problem man. Hey when u bolt them on and get some dyno figures let me know ok...

Jason

did some more searching on the internet, found this website that says the vortec heads had 2 casting numbers 10239906 and 12558062. no difference's were mentioned. www.streetrodstuff.com/products/115/.

They are just giving the 2 types of heads. But still the 906 heads are the better flowing heads.

Jason

Hey looking at what ur sayin about your IROC.. I have the same year IROC w/ a TPI. Just wondering what cam you put in and how did it help.

when i rebuilt the motor, (had block bored .030) i installed the comp cam for the 305/350tpi. it has .444 lift on both intake and exhaust. it helped some (i wanted to keep a good idle and vacuum so i didn't go too crazy) i'm looking for headers next. thanks, tom

I think Fbirdta878787 has the heads reversed. The 906's are the ones that flow less. In Chevy high performance jan '03 issue on page 40 they state that the 10239906 heads are for 3/4 and 1 ton trucks and have specially harded valve seats thats kills low end and mid range lift flow. I had the 906's on my engine in my 69 camaro and they run good but I think the other casting is better.

i know that my heads (062 casting) came from a 98 1/2 ton 4x4. (as i removed the motor myself and install a new GM longblock) i don't know, i was just wondering if there is a difference between the casting numbers. thanks, tom

ohh F U G G!! Can someone PLEASE verify what's what and what "flows better"?

Also, I have 2 sets one say "Made in Mexico" the other says "Made in Canada"....any knowledge on some possible differences?????

I concur with Todd. The article said to AVOID the 906's.

all remarks made about 906"s having less flow in hotrod magazine were retracted at a later date as these remarks were false. although it is advisable to blend the exaust seets to the port.

Indeed:

http://www.sallee-chevrolet.com/Cyli...ads/Vortec.cfm

Yup...Wow this is back from the dead. It has been stated that and proven that the 062 head do not flow more but have a stronger exhaust seat.

Sorry to tell ya, but Jason has it backwards. The 062 vortec heads are what you want for performance. The 906 vortec heads have a special hardened valve seat which limits its lift slightly compared to the 062 heads. But dont take either of our words, its the age of information & its literally at your fingertips, 1 thing ive found in these forums, each person has their own view & belief on any given subject, with that in mind, asking a public question is really just an open invitation to debate. Just read thru articles posted by published sources, HotRod magazine and the likes, youll find the info you seek, without having to filter through everyone elses opinions or beliefs. Just speaking from experience. Here's a good article from a well known, published source that was written by people that have actual, first hand knowledge on the subject.

http://www.onedirt.com/tech-stories/engine/a-guide-to-vortec-vs-oe-small-block-chevy-heads/

amen

I realize this is an old thread, but I couldn't possible disagree with this statement more fully. Published articles are bought and paid for, and written by enthusiasts just as fallible as anyone, and often have no more knowledgeable than many of us in these forums. Is there mis-information on forums, sure. -as well as some jack leg know it alls who don't know it all. You also have guys who helped BUILD these cars, or heads, or valves, or gizmos or gadgets back in the day, as well as guys who have built engines over and over and over. Been here about 20 years, and I've seen many of the big manufacturers and publications asking US questions about this or that. No I'm sorry, the best info is hands down, on the forums.

You just have to know how to sort through it all, -which I do concede can be difficult at times. Still, when I receive 10 opinions, I can typically put together a good picture of who knows what, who is the know it all new kid and who is the guy who knows his stuff. And sure, sometimes it may bite ya, but no way I'm reading an article in a magazine and taking their word for it! The metric crap ton of garbage info out there in the magazines would amaze you.

so anyone saying are different for flow is wrong the pattern to cast is literally the same the only different is the material used for the valve seat itself.

• Two Vortec castings were used from 1996-99 on GM CK trucks ('00 in vans) and SUV's utilizing the Vortec 5700 350 engine. The #906 and #062. The #906 casting head was available in two versions. One has an Inconel exhaust seat, and the other has the conventional induction hardened 3-angle grind on the exhausts as per the #062. The #906 with Inconel seat does not intrude into the exhaust port. It was used primarily on the HD and 1-ton truck applications where sustained towing of heavy loads & weight up inclines could cause eventual damage to a standard induction-hardened exhaust seat from excessive heat.
• The only difference between the #062 and #906 Vortec head is in the exhaust seat of the HD/1-ton truck #906 version, as described above. The #062 has a 3-angle grind on a standard induction-hardened seat, as does the non-HD #906 head.

Old thread but since people are on the subject. Mexican 062 Vortecs flow like crap. 218 cfm peak at 0.400 and dropped to 210 at 0.450 and beyond (heads off my Hecho en Mexico crate engine bought in spring of 2006). 059 305 Vortec heads outflowed the mexican 062 garbage. My Canadian 906s (off my 57K mile L31 97 Van with a rod hanging out of the block) peaked out at 242 @ 0.500. 906s were better everywhere and the factory 97 engine made noticeably more power yet they also had the HD single angle hardened seat. Both were flowed on the same bench with the same exact hardware and methods. The 062s both cracked, the 906s are still good. Etec170s wiped the floor with both castings. Better power and better fuel economy from the aluminum heads. I could only run 28-29° of timing on the iron heads with 91 octane before encountering detonation and the aluminum heads liked 34° by 2,600 rpm. Torque curve was much stronger with the aluminum edelbrock heads.

Hi not sure who will see this but I e been building engines since before the vortec heads were out I want everyone to know this the 906 casting heads are high flow heads they flow more period the 062 are the heads with a lower flow rate been that way since they were released the 906 heads are the way to go they are good up to about 385 horses before valve train really needs to be upgraded . So please know this is to stop all the confusion hot rod mag retracted that statement because it was released before any real testing was done now America knows 906 is the way to go if your trying to have a better flowing head somewhere I have all the specs on Flow rates I will post as soon as I find them thank you fellas hope this helps talk looking to use the better of the two castings

Factory production GM cast iron Vortec heads are junk and should be left in the junkyard, Craig's List, FB Marketplace, swap meet where you found them.

They are ultra light weight thin wall castings that are prone to cracking and warping. They were made for emissions and CAFE MPG standards. They are not high performance cylinder heads. They just happen to make 25 HP to 40 HP more than other factory production GM cast iron heads. They were a readily available and cheaper than dirt higher performance cast iron head option back in their "Vortec Head" heyday. Now they are nothing more than a washed up has been junk cast iron cylinder head.

Factory production GM cast iron Vortec cylinder heads should be avoided like the plague. By the time you go through 10+ heads to get two good rebuildable cores, spend the money on good quality parts to rebuild them, pay for the machine work at a quality machine shop you are already looking at the price of a good quality set of entry level aftermarket cast iron or aluminum heads that will outperform the redone Vortec heads. Also these days good quality machine shops with affordable prices are even more rare then a good set of crack free non-warped factory production GM Vortec cylinder heads.

The only cast iron Vortec heads that are any good are aftermarket Vortec style heads based off the Vortec design but not built off the factory ultra light weight thin wall castings. The good aftermarket cast iron Vortec style head weighs anywhere from 9lbs to 13lbs more per head than the factory production GM Vortec head.

There are good aftermarket Vortec style aluminum cylinder heads.

Vortec style heads whether cast iron or aluminum, factory or aftermarket should be avoided unless you absolutely have to have the Vortec intake manifold bolt pattern style due to the intake you needing or wanting to use being only available in the Vortec bolt pattern.

i prefer the Vortec intake bolt pattern based manifolds and cylinder heads. The raised intake runners make a difference.

SO, how about some Brand Names and maybe part numbers, for the Good aftermarket Vortec heads? Thanks.

nothing special about vortec heads they are gen 2 LT1 heads for a sbc, most all aftermarket heads now have those combustion chambers LT1 and LT4 where superior bc of the 54cc combustion chamber, better exhaust ports, and screw in rocker studs, the gm fast burns have the raised port and dual intake bolt pattern

you can buy used 93-97 LT1 complete engines for 500-1k stick a distributor in and run all your existing sensors ecu ect while having aluminum heads reverse cooling and higher compression

Are they the same as the heads on the 1996 Impala SS LT1 Long Block, that I gave to the scrap man, after storing it for years?

impala has iron heads but yes they are vortec design w/o the raised intake port they flow a bit more on the intake side compared to the aluminum found on camaros and vettes that impala engine with minor port work on the heads and a cam can make 400-450 horsepower

Over 500 hp with the right setup.

I gave the LT1 away when my wife and I moved to Utah.