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243's on a 4.8?

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Old Jul 7, 2011 | 12:40 PM
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Default 243's on a 4.8?

Anyone ever done it? If so how'd it perform and was it worth it?

I picked up some 243's today with 8k miles on them for $100. I got them for an iron block 5.7 I wanna build but thought about going ahead and putting them on this 4.8 for the time being. Just wondering how well these heads work with the 4.8?
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Old Jul 7, 2011 | 06:39 PM
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IIRC you'll lose a lot of compression and lose power. Would need to get them milled.

Again, I don't remember if that is correct or not, just off the top of my head that's what i think i remember hearing
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Old Jul 7, 2011 | 08:33 PM
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Mill them. They come oem on the 4.8s from about 07 and up. They are on my 09, but I don't know if gm uses different pistons to offset the larger chambers of the heads.
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Old Jul 7, 2011 | 08:50 PM
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Where did you find some for 100?
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Old Jul 7, 2011 | 09:46 PM
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I got them from a guy I went to school with. He bought them for his ws6 but never installed them cause he ended up getting a heads/cam package from TSP. He knew nothing about them and said he'd sell em to me for $100.
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Old Jul 7, 2011 | 11:23 PM
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yeah, the loss of compression will offset some of the gains from airflow.

How does the 4.8 like the tr220 cam?
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Old Jul 8, 2011 | 05:02 AM
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It loves the tr220. Pulls very hard, especially up top
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Old Jul 9, 2011 | 01:48 AM
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It will pull harder with the 243's. Get them milled, and get a pushrod length checker.
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Old Jul 9, 2011 | 04:35 AM
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I would def have them milled .030 - .040 to get the compression back up and might as well do a valve job and clean the bowls up while your there.
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Old Jul 9, 2011 | 09:21 AM
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Only thing I'm scared of is milling them too much since I plan on putting them on the 5.7 I'm gonna build. Probably better off just waiting I suppose, as bad as I hate to lol
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