sbc vortec head cracking problems

[chico68]

Recently bought a set of vortecs for a 400 build, took in for a complete valve job and found out they both were cracked. I couldn't believe it because there is so much hype about how good they are and how much HP you get switching to them. Also the magazines do these builds and don't mention the cracking problems, WHY! Any thoughts on this will be helpful, thanks Rob P.

[B. W.]

I'd say that 9 out of 10 used vortec heads taken to a machine shop will be cracked. With that said, I like them, but I always replace with new ones.

[LongBox]

What's the story here? Why is there such a cracking problem with these heads? I'd just like to know, and I bet others would as well.

[Italia's 67]

If you get the 906 heads they have hardened valve seats pressed in that are more durable. The 062 heads are just cast heads with the valves cut into them and are really prone to cracking.

[garyd1961]

I have heard of the cracking but I thought it was from people running them without a coolant bypass and over heating the heads. I do know I worked at a chevy dealership from 2007-2013 and I saw a lot of these trucks come in with 200,000 or more mile and still running good. Anyway I have the 906 heads on mine with a coolant bypass so I'm not concerned with cracking.

[special-K]

I've never had anything with Vortec heads. I considered them for my 327 build but went for pre-68 327 64cc heads. I'm looking to put a Vortec engine in my '95 Suburban right now. Not until just in the last month did I hear anything about the heads cracking. A member was saying they all do. I was surprised I never heard that before. So, for Vortec heads you want aluminum?

[YJ_Aaron]

It's extremely common on both the 906 and 062 castings. At least 1 in 3 will be cracked from a core engine.

That's why even the Dart iron heads are thicker castings.

[Boog]

I don't think cracked vortec heads is really all that common. Obviously they don't all crack. Like you Tim I have only recently heard mention of it. I've had several Vortecs with no problem, one with well over 200,000 miles, but then one with aluminum heads developed a crack in one around a head bolt hole. It ran fine but was losing coolant, into the oil pan. It had never been overheated in the 4 years we have had it. That was a $2000 repair.

[YJ_Aaron]

Last year we tore down several thousand and the ratio is consistent.

[Warrens69GMC]

get these

http://www.ebay.com/itm/141495929457...%3AMEBIDX%3AIT

[chico68]

The machine shop I use is a very reputable one, he says he seen a good number cracked. And after I got mine back I did more research and find more people than not have had cracked vortecs. Some say 9 out of 10 are cracked. Mine were cracked in the center exhaust seats on both heads, and they were the 062 castings not the 906 with the hardened inserts. Maybe the 906's would be the better choice due to the hardened inserts. I here so many good performance related things about vortecs, GM finally did something right in that department but they didn't learn their lesson about beefing up the castings.

[special-K]

Always learning. I remember '78 SBC heads were prone to cracking. Back in the early-80s I had a '78 with a 350 that started putting out a cloud of white smoke all at once, head gasket shot. I took the heads in to get magna-fluxed then rebuilt. I knew the owner of the machine shop and when they turned out to be good he told me that was rare because in '78 GM decided to take about 5# off the heads that caused the problem. He offered to take those so he could provide original spec replacements and give me a set of hi-performance heads someone never picked up...for the cost of a basic valve job

[Boog]

I did a little google and found numerous links to cracked vortec heads. If there are truly 1 in 3 or 9 in 10 failures it looks to me like there would be a large class action suit against GM. No?
For a lot of years now I have heard the Vortec heads were THE BEST bang for the buck in small block performance upgrades. What happened?
Are most of these crack failures happening on very high mileage engines or mainly those that have been overheated?

[B. W.]

No on the class action, they are long out of warranty. Most high mileage 5.7 vortecs that are running today probable have at least one cracked head, maybe both. The cracks are very minimal (I know, still a crack) many engines don't show any symptoms. I've torn down more than a few that were running well & found cracks. (not as many as Yj-Aaron!) My daily driver is a 99 yukon with 270 on the clock, my wife's 98 burb has 285 both have never been apart (excluding intake gaskets) Neither use fluids. I'm willing to bet that 3 of the 4 heads are cracked if we tore them down. If you want to run Vortec heads, go new. If your truck has vortec heads on it & the engine runs well keep running it & don't loose any sleep over it.

The Engine Quest vortec heads are good heads, cast in New Zealand NOT china. If i'm correct they took over from RHS (Racing Head Service) who stopped making the cast iron vortec heads. I have a pair of both EQ & RHS, they have the same casting #'s

[YJ_Aaron]

The old RHS were good heads we used them for years with no negative results. Now we use Dart for new vortec heads. I wouldn't hesitate to run a gm vortec, as previously stated most never show symptoms of the Crack and perform great.

[chico68]

Found this today on youtube. Have listened to this guy before, but have not seen this one until today, good info here. https://www.youtube.com/watch?v=wi_7NukwL8A

[James the III]

It's not just vortec's.. most light weight iron castings will get cracks..
One must also remember they are on trucks that are run hard and put away wet..
And do so for 200k+ ..
Why anyone rebuilds them is beyond me.. other than shops that can do it at a low cost..
as new ones are cheap.. under 700.00 complete..

[88Stanger]

i tried this Vortec head thought. Bought a set, one was cracked, bought another one and it was cracked, finally the 3rd one worked, now the bad news. i bought mine, checked the numbers and they are supposed to be 350 heads with 64cc, well i will tell you that they are the early center bolt heads, BUT they have 58cc not 64cc. I had a hell of a time getting it run right with way to much compression. so just think about that. Now, i have complete set minus rockers of vortec heads fully rebuilt with 98 miles on them sitting under the bench and now i have a set of aluminium heads with 70cc. i want a good decent daily driver not a compression monster. lol

[James the III]

Originally Posted by 88Stanger

i tried this Vortec head thought. Bought a set, one was cracked, bought another one and it was cracked, finally the 3rd one worked, now the bad news. i bought mine, checked the numbers and they are supposed to be 350 heads with 64cc, well i will tell you that they are the early center bolt heads, BUT they have 58cc not 64cc. I had a hell of a time getting it run right with way to much compression. so just think about that. Now, i have complete set minus rockers of vortec heads fully rebuilt with 98 miles on them sitting under the bench and now i have a set of aluminium heads with 70cc. i want a good decent daily driver not a compression monster. lol

you got 305 heads..