vortec heads work

[cplonner]

I have these vortec heads and it turns out that they are setup for a truck. this means they have a heavy duty valve seat that restricts the low end to meduim end flow about 20%. (read in chevy high performance). Is this a costly thing to have changed on these heads?
i already want to get them ported and polished,springs and studs setup for a higher lift and get some 1.6 rockers (this will make my lift .537). so i already want to have some work done to them.
I figure i would get a great power gain, but is it worth the money?
Thanks for any info you can spare

 

[Ken]

Hmmm... I never did finish reading that article. Thanks for reminding me.

 

[cplonner]

Does Anyone Know?

 

[Ken]

Sorry man, but I can't be of much help to you with this question. I was hoping one of our engine gurus would pick up on this post and have an answer for you. Hang in there, someone's going to see this eventually and they'll respond.

 

[RWDsmoke]

If I remerber correctly, there was a later article that said these were only on some of the heavy duty trucks, and the seats could be ground to remove the restriction. I'll try to find the article.

 

[RWDsmoke]

Found it. April 2003 CHP Department of corrections article casting #12558062 or #10239906 are both good. I am using the 10239906 castings which the earlier article said to avoid. I was very happy to see they are also the good castings as I already had the machine work finished on them. And mine came from a 1 ton truck. Thats all the info I found.

 

[cplonner]

cool, thanks for the info! thats really good to hear. Did you get your set up for a higher lift? thats what i was planning to do. If so what did you have to do and was it a pain or expensive?

 

[RWDsmoke]

I had the valve guides cut down and the spring seats enlarged and installed screw in studs. I also drilled out the pushrod holes so I can go to 1.6 roller rockers later. Don't remember what the cost of all that was. I had the block bored and everything balanced at that time, too. I'm using a hotcam and an lt4 intake.