scottylow

iTrader: (1)

So I have read a lot about the 243/799 heads being the best stock heads but I have also heard that the 317 heads flow just as well. I did some research and and it seems the biggest difference is the lower compression on the 317's. So is this the only major difference between the 2? If so I have seen the 317's going for quite a bit less that the 243/799 heads would it be worth it to buy them and mill them down to bump up the compression? What would be the side effect of the besides the intake not fitting properly? I am going to freshen up my stock ls1 and I plan on camming it and running a ls6 intake. Just looking for something fun on the street thats reliable without breaking the bank.

bww3588

iTrader: (49)

Same head other than the chamber. Down side to milling, is you have to take around .030 off to match a set of ls6 chambers. That leaves the head deck thin and can cause intake fitment issues

87caprice318

iTrader: (1)

Has anyone milled them .030 and had that fitment issue? Or if someone has milled them .030, what did they do about the intake IF there was a problem?

Bruce Pittman

iTrader: (2)

would like to hear +/- on this too, since 317s can be had all day long for about $100 for the pair sometimes even less. some truck guys are pulling these off thier LQ4s (not 100% on OE fitment) and have them taking up space so they practically wanna give them away (i just jinxed it, now the prices are going up)

ss454327

iTrader: (10)

I don't know about cheap but you could have the chambers welded to take up some of the space and give you more CR without giving up deck thickness or PTV clearance.

MPFD

iTrader: (5)

Decks are fine, that's a wives tail. No need to worry about intake fitment till you mill over .040" and only problem with milling is PTV clearance. I know several guys personally that have milled L92's .060"...

Sales4@Texas-Speed

iTrader: (4)

Intake fitment would not be anything to worry about. Piston to valve clearance would be the thing to worry about depending on your cam size. I have seen heads milled .060" and not required any changes to intake for fitment.

PREDATOR-Z

What you can do is send the 317s to AI for porting and have them fill the chambers to desired CC. This keeps stock PTV clearances and increase compression (not to mention flow)

scottylow

iTrader: (1)

So from what I am reading I can mill them and my major issue would be piston to valve clearance. Any ideas how big of a cam I could run if I milled them .030. Ballpark numbers. Obviously I'm not trying to go crazy but I want something that will sound good and maximize my usable performance as a street car.

Redbull87

iTrader: (3)

Im curious about this too.I want to start planning my next phase of mods starting with long tube headers,rear gear,and keep my 317 heads but mill them down and keep my 228r/pac springs/7.4rods if I can and still use my ls6 intake.Just looking for a good number of how much to take off and what my compression might be close to.Tsp ..any suggestions?Im only shooting to hit 400rwhp from my current 352rwhp on stock manifold.