Gen V Heads HELP!

Carrera J said:

Does anyone know what heads came on a 08/92 production 7.4 Carb, 300hp. Bravo1 ? Mercruiser said Oval Port but couldn't say which ones. Should they be "peanut ports" or larger Oval. I would like to switch out to 049's. Will this Gen V support or is the compression going to be a problem?
Thanks

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049s are a MkIV head and will not work on a GenV block. There will be a mismatch in the cooling passages at the lifter valley side of the deck.

http://www.strokerengine.com

Click the link, go to the Big Block Chevy section and scroll all the way to the bottom and it will show you the difference between the cooling passages between a MkIV and a GenV.

I think I remember hearing about a company that might make a special head gasket that will adapt a set of MkIV heads to a GenV block, but the experts may wanna chime in on that one.

Thanks, I thought that I heard before that the Gen V was a different set up.

Jetaholic said:

049s are a MkIV head and will not work on a GenV block. There will be a mismatch in the cooling passages at the lifter valley side of the deck.

http://www.strokerengine.com

Click the link, go to the Big Block Chevy section and scroll all the way to the bottom and it will show you the difference between the cooling passages between a MkIV and a GenV.

Click to expand...

except for one obscure sentence that seems out of place and doesn't make much sense, this guy is talking about Gen 5/6 heads on Mark 4 blocks, not the other way around.

Mark 4 heads fit all blocks, 4/5/6

take a look at all the aftermarket heads, and see what design they use.

5325user said:

except for one obscure sentence that seems out of place and doesn't make much sense, this guy is talking about Gen 5/6 heads on Mark 4 blocks, not the other way around.

Mark 4 heads fit all blocks, 4/5/6

take a look at all the aftermarket heads, and see what design they use.

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I stand corrected. I was wondering about that...as I looked at the pics of the GenV deck it looked to me like a MkIV head should work on a GenV block, but I could definitely see how GenV heads would absolutely NOT work on a MkIV block.

Carrera J said:

Does anyone know what heads came on a 08/92 production 7.4 Carb, 300hp. Bravo1 ? Mercruiser said Oval Port but couldn't say which ones. Should they be "peanut ports" or larger Oval. I would like to switch out to 049's. Will this Gen V support or is the compression going to be a problem?
Thanks

Click to expand...

If the ovals on the 7.4 are the Vortec, I believe they have 100cc chambers, where the 049's will have 119cc so by swapping, you'll lose compression.