Cylinder Head Digest

[Quickstop [UK]]

Re: Cylinder Head Digest

A cool link for what goes on inside...

http://www.liveleak.com/view?i=73e_1192001762

 

[WyoSyclone]

Re: Cylinder Head Digest

I would really like to see a source that lists casting numbers for Vortec heads that have hardened valve seats. I think that all marine castings came that way, but none of the automotive ones did. I've never been able to find a source that lists the marine castings.

FWIW, the casting number of my heads is 12557107 and they do have hardened valve seats.

I think I've got this cylinder head spread sheet just about done. From what the spreadsheet shows me, you're right with regard to the Marine heads having the hardened seats (the very few sources I've found list them as a "772 with hardened seats"). All of the sources also list the Marine heads as having a slightly thicker casting, which seems very strange (almost like a 3rd party foundry produced them, rather than GM's normal supplier).

It also seems there may be a possible difference in 772 castings. I keep finding reference to the Z and W vin versions having bigger ports, as opposed to the 1998 X vin version. The W vin is also referenced as an HP version, as opposed to the X vin non-HP. Some confusion as well with regard to 10mm screw in studs on the X and W, as opposed to 5/16 on the Z.

 

[It's just a six]

Re: Cylinder Head Digest

For the most part,I think the GM cast iron heads we are talking about here have induction hardened exhaust valve seating areas,it is really hard,not sure on how deep the hardening actually is.
I can ask my friends cyl head shop.

 

[WyoSyclone]

Re: Cylinder Head Digest

For the most part,all GM cast iron heads we are talking about here have induction hardened exhaust valve seating areas,it is really hard,not sure on how deep the hardening actually is.
I can ask my friends cyl head shop.

If you could ask him if he knows of any difference between the standard truck heads, marine heads, and HD truck (gvw over 8500lbs) that would be great. Thanks!

 

[It's just a six]

Re: Cylinder Head Digest

If you could ask him if he knows of any difference between the standard truck heads, marine heads, and HD truck (gvw over 8500lbs) that would be great. Thanks!

Not sure if he will have that info, but I'll ask.
They mainly specialize w/LS GM heads now, but they still do different heads.
Very well respected on LS forums.:tup:

 

[It's just a six]

Re: Cylinder Head Digest

Talked w/my friend,no idea on differences on heads.
But on all newer GM V-8 marine heads,all have exhaust inserts,before they did not all have them.

The induction hardening is not that thick. Most all newer cast iron heads have inserts he also added.

So it seems,get the heads that are not inductioned hardened (if possible) causes stress to the heads & could possibly crack,that's part of the reason why the newer heads have exhaust inserts.

 

[nallj92]

Re: Cylinder Head Digest

Sent you out a excel file i made with flow #'s gathered from this site. I worked on it a while back when researching and porting my vortecs myself. I can also gather info off my GM 18 deg's this weekend. What do you all need/want? specific pics?

later

 

[mowglie]

Re: Cylinder Head Digest

Good info. Wonder what the L35's flow compared to stockers

 

[Sportmachines]

Re: Cylinder Head Digest

We have been looking at this lately. Might be more info:

http://users.erols.com/srweiss/tablehdc.htm

 

[WyoSyclone]

Re: Cylinder Head Digest

According to info from Justin (taken off the forum here), and from the Stan Weiss website....

@500 intake exhaust

LB4 stock 165 119

L35 stock 189 ? (230/195 ported)

Vortec stock 216 163 (259/191 ported)

 

[WyoSyclone]

Re: Cylinder Head Digest

We have been looking at this lately. Might be more info:

http://users.erols.com/srweiss/tablehdc.htm

Yup, that's the one I've been using for a while now too.... some great info.

 

[Sy777]

Re: Cylinder Head Digest

The l35 heads were used up until 95 on the 4,3 so the 94-95 heads would be desired.

 

[V8 Sonoma GT]

Re: Cylinder Head Digest

so from what i have been reading, vortec 772s are the best ones to get? off a 96/97 is that correct?

 

[It's just a six]

Re: Cylinder Head Digest

Yes the 96 & newer heads are better but will not pass a smog check, no exhaust to function with the EGR valve.

If that is any concern.

 

[V8 Sonoma GT]

Re: Cylinder Head Digest

that is not..so i have a line on some 113s with rollers for 100 bucks

 

[It's just a six]

Re: Cylinder Head Digest

that is not..so i have a line on some 113s with rollers for 100 bucks

What exactly is not so?

 

[V8 Sonoma GT]

Re: Cylinder Head Digest

that is not so as in a concern for smog. we have no emissions.

 

[It's just a six]

Re: Cylinder Head Digest

Gotcha.:tup:

 

[dgoodhue]

Re: Cylinder Head Digest

It really depends on if the emission station is going to test for EGR operation. It should pass a sniffer test with/without EGR. The only state I have heard of anyone checking EGR is CA.

 

[It's just a six]

Re: Cylinder Head Digest

It really depends on if the emission station is going to test for EGR operation. It should pass a sniffer test with/without EGR. The only state I have heard of anyone checking EGR is CA.

Yep, they check it here in Cali.:tdown:

I would think other state smog stations are supposed to check it also? But not sure.

Any other states check for EGR function other than Cali?