A couple of 5.3 head options.
02-29-2012, 08:20 AM
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A couple of 5.3 head options. I'm currently building a 5.3 for use in a jet boat. The bottom end is stock but has been freshened with new rings and bearings. I had the cam custom ground to 226/229 .575/.578 on a 114 lsa. With the cam grind I now have a smaller base circle and need pushrods that are .025 longer. That's one option. The other (and cheaper) option is to get the heads milled. I have two options here.
First is to get the 5.3 852 casting heads milled which will raise the compression a full point and make more power. The second option is a set of 853 Vette heads I have. I've read getting those heads milled .030 will raise the CR by like a quarter point over stock.
At some point later in the year the boat may get a procharger on it, so I'm leaning toward the 853 heads. They have a bigger intake valve. Although both heads flow about the same NA, under boost the bigger valve should have the advantage. But for now the higher CR of the 852 heads would definitely have the advantage.
Looking for 400 ponies hopefully. Thanks for the replies.
First is to get the 5.3 852 casting heads milled which will raise the compression a full point and make more power. The second option is a set of 853 Vette heads I have. I've read getting those heads milled .030 will raise the CR by like a quarter point over stock.
At some point later in the year the boat may get a procharger on it, so I'm leaning toward the 853 heads. They have a bigger intake valve. Although both heads flow about the same NA, under boost the bigger valve should have the advantage. But for now the higher CR of the 852 heads would definitely have the advantage.
Looking for 400 ponies hopefully. Thanks for the replies.
