Milled 317 heads, or LS6?
Milled 317 heads, or LS6? I'm looking at getting some new heads, and am trying to decide between milled 317's or 243's. I can get the 317's cheap, and I'll get them milled down to 66 cc. This is my dd, so my goal is to keep low end power. I'm planning on installing Vengeance Racing's VRX3 cam, and so I was trying to figure out what would give me the best results.
Thanks
Thanks
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Although a 317 is basicaly same runner design as a 243 it has 72cc chambers instead of 65cc on stock 243.
So by milling to 65cc, yes you would get similar results, EXCEPT you now are limited on the cam size you can fit under there because of the mill.
7cc mill is .042 mill and loss in piston valve clearance.
I read his post Please read OP post before posting. That is exactly waht OP wants to hear but is not fact.
Although a 317 is basicaly same runner design as a 243 it has 72cc chambers instead of 65cc on stock 243.
So by milling to 65cc, yes you would get similar results, EXCEPT you now are limited on the cam size you can fit under there because of the mill.
7cc mill is .042 mill and loss in piston valve clearance.
Although a 317 is basicaly same runner design as a 243 it has 72cc chambers instead of 65cc on stock 243.
So by milling to 65cc, yes you would get similar results, EXCEPT you now are limited on the cam size you can fit under there because of the mill.
7cc mill is .042 mill and loss in piston valve clearance.
just because someone doesnt share your opinoin doesnt meen you have to be an *** about it....
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Verdad Gallardo TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
uhh i read his post...and he only needs .030 to get the 66cc chamber thar he said he would mill them to...the 317s have a 71cc chamber...the never said he wanted the heads milled to match the 243 chamber....ive purchased 317 heads for 200 bucks hell ive seen them go cheaper....around here it costs 25 bucks a head to get them milled....the cheapest ive seen 243s go for is around 400 a set...
just because someone doesnt share your opinoin doesnt meen you have to be an *** about it....
just because someone doesnt share your opinoin doesnt meen you have to be an *** about it....
Your answer is still ill advice, what he needs is to know which will benefit him more, and the answer is still 243s, I said 317s were "similar" but not identical. Catch my drift?
He is right though. Milling is gonna eat up valuable piston-valve clearance and flycutting will only weaken the cast pistons, not to mention expose the engine to metal debris if done in the car. Why do all that just to jerry-rig some heads to work, when you can just do the 243 route and be able to mill more later.
I'd go for the LS6 heads, that way you have the option to mill more later and get those nifty valves.
guys i did say that unless the 317s were dirt cheap to go 243......yes the 243 is abetter head i think it flows about 15cfm more on intake and a little more exhaust.....bothg 317 and 243 flow better than any stock ls1 head.......
honestly i wouldnt do either 5.3 all the way....
honestly i wouldnt do either 5.3 all the way....
Definately look to the LS6 heads over the 317 heads. Predator is exactly correct. Giving up .040" of clearance to make a 317 fit on the head is not worth it at all. On top of that the chambers are setup for different bores.
Look to someone with a good cnc ported LS6 head & you'll have a 40hp gain for right about $1000 or so. We sell PRC LS6 heads that can except upto .020" of milling & still keep stock piston to valve clearance!!
http://www.texas-speed.com/shop/item...d=649&catid=20
Look to someone with a good cnc ported LS6 head & you'll have a 40hp gain for right about $1000 or so. We sell PRC LS6 heads that can except upto .020" of milling & still keep stock piston to valve clearance!!
http://www.texas-speed.com/shop/item...d=649&catid=20
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Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
