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-   -   Head Compatibility Question (https://www.offshoreonly.com/forums/general-q/277017-head-compatibility-question.html)

endeavour32 05-23-2012 08:10 PM


Originally Posted by HaxbySpeed (Post 3694475)
There's no problem running Gen VI heads on a Gen IV as long as you use the right gasket. If you end up going this route let me know and I'll give you a part number.

Yes- let me know what gasket I need. For $500 for brand new heads I'd be a fool not to. I've read in some posts that you need to scribe the outline of the lifter valley so you can see how close the water jacket is. Is this so? If so, at what point is not enough overlap?

charliem 05-24-2012 12:01 AM

http://www.chevelles.com/forums/showthread.php?t=316022

Use a quality gasket correct to your block. Careful to check water passages near lifter valley. This is where you would get leakage.

tcwcar 05-24-2012 06:44 PM


Originally Posted by HaxbySpeed (Post 3694475)
There's no problem running Gen VI heads on a Gen IV as long as you use the right gasket. If you end up going this route let me know and I'll give you a part number.

so let me get this straight, you can use the 088 genvi heads, on a geniv block with the right gaskets, is that right Haxby speed....:evilb:

HaxbySpeed 05-24-2012 06:51 PM


Originally Posted by tcwcar (Post 3695218)
so let me get this straight, you can use the 088 genvi heads, on a geniv block with the right gaskets, is that right Haxby speed....:evilb:

Yes, and depending on which Mark IV block you've got it's also a good time to convert it to parallel flow vs. series.

endeavour32 05-25-2012 03:46 PM

Haxby-
I picked up the heads today, what gasket do I need. From what I can tell my block has the three holes that are needed.

HaxbySpeed 05-25-2012 04:32 PM


Originally Posted by endeavour32 (Post 3695792)
Haxby-
I picked up the heads today, what gasket do I need. From what I can tell my block has the three holes that are needed.

What's your bore size?

endeavour32 05-25-2012 06:15 PM

1 Attachment(s)
It's 4.25. Here is a picture of the deck as well... Yes, it's being resurfaced, dropped the block off at the Machine shop this morning when I picked up the heads.

HaxbySpeed 05-25-2012 07:08 PM

Felpro 17042 will work fine and will give you parallel flow which the block is already set up for. :ernaehrung004:

endeavour32 05-25-2012 07:09 PM

Perfect and thanks for your help!

HaxbySpeed 05-25-2012 07:22 PM

No problem, the spot that has the most trouble is the upper hole between 5 and 7. You can lay the head on the block with no gasket and mark the edge with a sharpie to make sure you're gonna have enough squish there before you put it all together. Never hurts to double check everything.


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