317 cast head help please
11-03-2009, 07:24 PM
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317 cast head help please Im looking to upgrade my heads (853's now) on my cam only ls1 and a buddy has a set of 317 cast heads that he would sell me for $100. Are they worth getting and what would I have to do to them to get them milled, valve job etc... to get these to make decent gains on my car? How much roughly would the machine work cost? The cam in it now is a Ms4 (239/242 609/649 I believe). I would swap out my upgraded springs and all to these heads as well. Would all this be worth it and how much could I gain off of doing this head swap? Thanks for the help!
01-05-2010, 09:05 PM
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I believe the 317s are like the 243s but with a larger combustion chamber and lower compression. they are good for boosted applications. I have heard that when they are milled they are the same as 243s. I'm interested in hearing more opinions though, 317s seem to be cheaper than 243s
01-06-2010, 11:01 AM
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I would buy those heads but only to turn around and sell them again to make some money.
With a big cam like the MS4, you need all the compression you can get. I would look for a LS6 head to start from if you are looking for a GM casting. The problem with the 317's is they come with a 72cc chamber. With the MS4, you really can't mill the heads unless you are flycutting the pistons. You can CNC the heads and pick up some flow but at the point you can go LS6 heads and get the flow and compression, that's the way I would go every time. Let me know if you have any questions and we'll get you fixed up!
Jon
With a big cam like the MS4, you need all the compression you can get. I would look for a LS6 head to start from if you are looking for a GM casting. The problem with the 317's is they come with a 72cc chamber. With the MS4, you really can't mill the heads unless you are flycutting the pistons. You can CNC the heads and pick up some flow but at the point you can go LS6 heads and get the flow and compression, that's the way I would go every time. Let me know if you have any questions and we'll get you fixed up!
Jon
