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-   -   #906 Casting Vortec Heads (http://www.hotrodders.com/forum/906-casting-vortec-heads-138833.html)

stfinney 05-17-2008 09:05 PM

#906 Casting Vortec Heads
 
Can anyone confirm the stories about the #906 vortec having a problem with the exhaust seat? I read that some 906 heads had a problem with the pressed in seats. Is that true and if so, what kind of problems can be expected?

techinspector1 05-17-2008 10:29 PM

from the Sallee Chevrolet discussion board.....
http://www.sallee-chevrolet.com/Disc...3418/4252.html

Mustangsaly 05-18-2008 06:29 AM

IMO if your building a street machine that is a strong soild engine and for fun and maybe a couple 1/4 or 1/8mi runs to see what ya got, no need to be afraid of the 906s. my buddie is in the office of a salvage yard, and the circle burners (stock car boys, mostly dirt, some asphalt) buy a lot of stuff from him. they aren't scared of the 906s. when the call for vortec heads, they buy the vortec heads in the best shape that the yard has at the time. they like the heads checked for cracks B4 driving and picking them up. there not after the head by #s. or most aren't. most of these stock car teams are building there own engines, but theres some world class record holders in the bunch too. I have a set of 062s but only because the price was right, I had a set of 906s I sold, just so I could keep a nicer set of heads in the best shape, and they happen to be 062s. and the 062s I got are in super shape and crack free, with a new set of comp 26918-16 beehive springs. others might say different.

stfinney 05-18-2008 06:37 AM

I guess I need to take out an exhaust valve and see if they have the pressed in seats or not. They heads are going on a mild 350 bored .060 over. It's not a daily driver, just my fullsize truck I use for hauling and towing once in a while and pulling our boat. How can I tell if they are GM factory heads or aftermarket cast iron vortecs?

F-BIRD'88 05-18-2008 06:40 AM

The only difference between the 062's and SOME 906's is SOME 906 vortec have a pressed in hardened exhaust seat as oppoesed to a factory flame hardened exhaust seat. The pressed in seat just flows a bit less than the other heads seat. Simple bowl porting (blending) under (deeper) the seat will eliminate any real or perceived difference in flow by eliminating the mechined metal "edge" left from the OEM manufacuring process.

A little hand blending fixes them right up.

Mustangsaly 05-18-2008 07:38 AM

for a fullsize truck you use for hauling and towing once in a while and pulling our boat, use 906s or 062s what ever you can get, no diffrence in your case. How can you tell if they are GM factory heads or aftermarket cast iron vortecs ? well GM vortecs will be from 1996 to 1999 and be numbereded 12558062 10239906 and prob say GM on them and have the saw tooth marks cast into one end of each head. others will prob chime on. do a google search on vortec heads

CNC BLOCKS NE 05-18-2008 07:54 AM

We have used alot of the 906 castings over the years on our circle track engines and with the proper bowl hawg and valve job the the step blends right in and is not an issue.

We have found on the Mexican castings that the intake runners are smaller and do hurt power on the dyno.

Good luck with your build Carl

bondo 05-18-2008 10:37 AM

Ayuh,......

I spent most of my internet time at iboats engine, I/O forums,....

The 906 Vortecs are the Go To heads for Us boaters,.....

They seem to be a bolt on 20/ 30hp in most cases,+ the Exhaust Seats are a Big Plus,....
Due to the fact that boat motors are Always pulling their guts out, running Uphill all the time.....
And being held at about 4800rpms with the prop loads, it's believed that, that great Big Seat helps cool the valve even better....
Tuliped exhaust valves seem to come by less often....

I've got a set of 906s going on my 383 motor for my on-going Hull refit..... :mwink:

stfinney 05-18-2008 12:37 PM

I am using the 624/882 heads right now and can't wait to install the vortecs. I got a new intake and gaskets on the way and a new 260 duration cam for great torque output. It's in a fullsize heavy 1972 truck with a 350 bored .060 with stock gears (later to be 3.73), stock torque converter and 600cfm Edelbrock carb, HEI ignition, 2 1/2" true dual exhaust with turbo mufflers and chrome 3" tips and 1 5/8" headers.

Mustangsaly 05-18-2008 12:49 PM

Quote:

Originally Posted by stfinney
I am using the 624/882 heads right now and can't wait to install the vortecs. I got a new intake and gaskets on the way and a new 260 duration cam for great torque output. It's in a fullsize heavy 1972 truck with a 350 bored .060 with stock gears (later to be 3.73), stock torque converter and 600cfm Edelbrock carb, HEI ignition, 2 1/2" true dual exhaust with turbo mufflers and chrome 3" tips and 1 5/8" headers.



you done any math yet on your compression ? cause your heads on your engine are around 76cc, and the vortecs are around 64cc. witch will up your comppression.

curtis73 05-18-2008 12:55 PM

I have actually used the 062s and 906s on the same engine; one of each. They both had a three-angle valve job, so effectively they are the same head now.

stfinney 05-18-2008 01:13 PM

No, haven't done any math for compression yet. Not sure what the pistons are until I take the old heads off. Using a stock thickness head gasket with the new heads. Maybe 9.5 to 10 possibly, not sure. Will check piston to deck height and all when engine is out for repaint and upgrade.

stfinney 05-18-2008 04:39 PM

Vortec Heads
 
2 Attachment(s)
I took out one of the exhaust valves and it looks to have the pressed in seat, but it looks as though it has been cleaned up already. There are no edges at all, it is very smooth all the way to the seat! Yay!

stfinney 05-18-2008 09:25 PM

Ok, I am not really familiar with center bolt valve covers, so I have a question. I know there is the PCV valve and the oil fill cap, but what is the small hole for? It is about half the size of the PCV valve hole. I am clueless!!

Xero420 07-24-2008 02:13 AM

5 Attachment(s)
Stfinney,

Your vortec heads are from GM and for 3/4 and 1 ton truck. You have a single ground valve with the harden set installed. GM did this to keep the exhaust valve cooler under heavy load, and pulling that load for a long time. Vortec heads like to crack on the exhaust valve down the runner with out over heating. It was a big issue for GM, and they came up with the install seat to fix the problem.

If you are going to use the vortec heads for a truck to pull heavy loads. Keep the seats, and use the single ground valves. You wont crack the heads, and will get a long life out of them.

If any one can help.
I am trying to find info on the 906's to tell if it came with small ports, or large ports. I have a set of 906 vortec with three angle ground valves. Witch should be the sawtooth heads. But this set of heads don't have the sawtooth on the ends. Nor do it have the bowtie, and GM castings. If any one can lead me to more info, or tell me more about these heads.

I thank you.


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