About 1 1/2 years ago i bought a set of Vortec heads off of ebay.

They were shipped to me with 15k miles on them and after I bolted them on ( after I shaved them to 56cc) I found that they had a bent valve. Fixed that and no real problems since. Anyway that car is in Hawaii and I'm gonna do some work to it when I go home for x-mas.

I recently found out that the casting # 10239906 is a crappy model because the exhaust seats are hardened and it makes for bad low rpm flow on the heads.

I'm gonna be really pissed if I find out that these are the heads that I have. The good ones are # 12558062.

My question is this:

I have not searched for a casting # on a head before, only on a block. I've seen in pictures that the # is on the underside of the ports = non- visible when installed.

I will be taking the valve covers off to put some roller rockers on, is there a visible casting # when you take the valve cover off???



I sure hope so. I sold my other car ( 83' Z-28) for $1,050 and am gonna use that cash to build a 355 motor for my RS. I'm planning on still using these Vortec heads. I just don't want to put the extra cash out to cure the problem if they are #906 castings.

 

Sometimes these hot rod mags do more harm them good.
A recent article apparently stats that the 906 heads are NFG.
Well the truth is only some of the 906 heads have pressed in hardened ex seats and even if yours do any lack of flow can be corrected with a simple pocket blend job. Production heads often have a ridge just below the valve seat where the head was machined to accept the valve seat. Most of the ones you'll find are the 062 heads any ways. Don't loose sleep over it.
Any difference in flow will be more than other stock heads any ways. You can locate the casting # under the valve cover, between the rockers.

 

That's what I thought, I couldv'e swore that the last time I was tuning w/valve covers off, I saw some #'s.... mustv'e been the ones I'm lookin' for huh!!!!

About most #'s being #062, I don't know about that. I checked out ebay right now and there are like 6 or 7 sets up for grabs 5 or 6 of them are #906.

I know the pocket porting doesn't seem like a big deal but I'm a perfectionist so I'll have to pu new springs on there, a 3 or 5 angle valve job..... shoot i"ll probably even want to port and polish them! I get carried away, that's why they are beeter off just being # 062 so when I get my 355 I can just put some new springs on um', slap um' on and go!

 

Does anyone else have any experience with casting #906???

How about the difference in flow numbers for the 2 different castings???

That would help me out a lot.

 

1. Why Why Why buy from ebay? Most of the vortecs on ebay are used/ used up or in need of work. Junkyard take offs.
And they end up selling for at or near what new ones cost.

New castings are cheap .... buy new... You'll save money.

2. Sorry----- None of that makes any sense.
thats all irrational double talk . You'd be best to just bolt them on as is as you can/will easily reduce the flow of these heads with some wacky valve job. Especially on the intake port.
Sorry--- don't mean to flame ya but your over thinking this
and worrying about something you know little or nothing about.
Unless your an expert on head porting and have a flow bench
to varify any gains, you'd be best to not try to improve the ports
on these heads for moderate to street/strip power.
These heads don't work that way. Take it from some one who has tried it.
Do the spring and guide mods and bolt 'em on.

 

thanks for the flame. and you can go ahead and not reply anymore.

It's not double talk. I'm just saying that I'm gonna wanna do more than a pocket blend job, that's all.

Oh yeah, they 15k miles on them and i got them for 340 shipped. That's why you should buy from Ebay, saved over 100 bucks. Sure they had a bent valve but whatever, it cost me like 30 bucks to fix, gasket and everything.

Oh and about me not knowing anything, unless you are a machinist, kiss my a$$ if you think I don't know anything. Just cause you can't understand what I'm TRYING to say doe not make me inferior in knowledge.

 

Maybe not, but you're showing you're inferior in listening to someone you knows what he's talking about.

I don't have any experience porting the Vortec heads. The reason is I've read about 5 different magazines, and 3 different books that say "Don't mess with them."

I'm not trying to swarm you or make you feel "inferior". I'm just suggesting that you not blow up at people when they give you valuable advice.

These aren't camel hump heads where any porting you do can do nothing but good. The Vortec heads are FAR superior. If you make the port just .010" too large in the wrong area, you may loose 10% or more air flow over the 'out of the box' flow numbers.