5.3 with 243 heads
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Teching In
Joined: Mar 2017
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5.3 with 243 heads I have a 5.3 out of a 02 Chevy Silverado. I am planning on putting 243 heads and 5.3 btr stage 3 cam with arp bolts. My question is do I use the 5.7 or the 5.3 headgaskets? Should I get the heads milled? Any help would be great Thanks
You may also want to look into using flat top pistons from an L33 to not lose any compression. If not, I would definitely mill the heads. You need 3.910" bore head gaskets. I am pretty sure both 5.7 and 5.3 use the same head gasket, at least in bore size. You may want to look into getting your Quench into a more desired range (.035-.040") which can be changed by head gasket thickness.
TECH Addict
Joined: Aug 2005
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From: Monroe,NY
The 5.3/5.7 are the same head gasket stock. They put both engine #'s on the head gasket. If you don't mill the heads you will lose compression since the stock heads are 61.15 cc and the 243's are 64.45 and you probably won't feel any difference. You can also use a thinner head gasket to help improve compression. I would mill and use the thinner head gasket.
TECH Addict
Joined: Aug 2005
Posts: 2,305
Likes: 126
From: Monroe,NY
The 243 heads unmilled will drop your compression to 9.16:1 with stock being 9.5:1. A .041 head gasket with stock being .051 will bring it to 9:36:1 and milling the heads to 58cc with the .041 head gasket should put you at 10.07:1.
