Hi guys looking to get some advice. I have a 2000 M6 Coupe with about 50k miles on it that I just got in February. Recently had it dyno tuned and it put down 352/346. Current mods are ls6 intake, ported and polished tb, blackwing, TPiS long tubes, x-pipe, corsa pace car exhaust, 160 degree t-stat, spec stage 2 clutch, comp 212/218 .522/.529 114 lsa cam, and b&m ripper shifter.

I just bought a set of Wegner racing ls2 799 heads that are 5-axis CNC'd with stock sized del west titanium valves. The heads were used on the K&N series NASCAR motors and flow 305/235 intake/exhaust (the porting was more focused on good low/mid numbers). They have stock sized 64cc chambers.

I'm trying to decide on a good cam for this setup. I want to have a street/strip car, hopefully 430+ rwhp (not chasing an ET as I don't want to grenade my rear end, but I'd maybe track the car 3-4 times a year) that can take care of most other cars from a 40-60 roll (on a closed course... Obviously )

Right now I'm leaning towards the G5x3 112 lsa cam kit, but I'm interested in what you guys' opinions are and if I should have the heads milled at all to maybe 59-61cc to bump up the compression ratio so I don't lose all my torque down low. Since the heads were designed for better flow mainly in the low/mid range though, I don't know if this will be necessary or not.
If any guys are running the g5x3 with ported 243 heads I'd love to hear from you - lots of people I know are running the g5x3 with afr 205's but it's harder to find the guys with 243's.

Like I said, open to suggestions on the cam but I am impressed with what I've seen from the g5x3. I'm just trying to get some opinions on what I can do to maximize my combo - I don't want to be one of those guys that just throws a pair of heads and cam together and hopes that they work well with each other. I've read enough to know that unless you maximize the flow dynamics of your combo you'll be missing out on a good chunk of power.

Thanks guys

 

Nobody has any opinions?

 

Subbed for the answers as I might go a similar route.

 

You may need to flycut your pistons with that cam and milled heads. Also, here is a quote from someone on another forum who is very cam knowledgeable: "From what I could gather around here, the G5X3 is 234/242, .600/.610 112/114 lsa (could be 236/242, .600/.610 112/114 looking at lobe charts)
Putting a cam that big, you'll loose low end response, no if/but about it, tighter gears are in order to soften that effect. (4.10/4.33) but you'll loose top end speed."

Based on what you are looking for, I think that cam may be too much. I am running the AFR 6016 cam, 224/228 duration, and met you hp goals and in the mid-range it really scoots. I am running AFR heads with similar flow and compression. You may not need a huge cam to get what you are looking for, which from your explanation, is area under the curve and not peak hp.

 

VN=
Those sound like good factory size head, and I would advise having them milled. Better economy, and more power. The G5 is a old design, and many have found no need to go that big on a street car. Maybe think about getting a trans brace. I like my ECS, and it may extend the life of your factory diff.

 

You'll get 430rwhp outta that, especially if you use a FAST intake. Might even creep on 450 w/ a FAST, if the heads are truly what your being told. Your gonna be cutting it close on PTV. You need to measure and see where its at. Thinner head gaskets(cometic or felpro) can give you that bump in compression and tighten quench up if the clearance is there. Win Win.

G5x3 seems to always make power with a solid pair of heads however it'll be tough on the valve train. Good valve train will be important.

 

So that being said do you think it'd make sense to get a cam custom spec'd?

I just got in contact with Wegner yesterday and they're going to send me all the numbers on the heads (flow data etc.) so I'll know everything about them. I'm thinking that the titanium valves will help lighten up the valve train quite a bit (intake is 68g and exhaust is 55g) and I'd definitely be running dual valvesprings (even though the nascar spec motor with these heads ran beehives) with stock rockers with the trunion upgrade. I'm hoping this will allow me to bump the rev limiter up to maybe 6800 or so without causing too much stress but I'm not sure how the stock bottom end will hold up under those kind of revs. The guy at wegner said that people would rev their motors up to 8-9000 rpm with these heads and be okay but obviously that's on a forged bottom end.

Making the car a little less streetable isn't too big of a concern as I'll have another car for my DD before I do the cam. The whole "do you want torque or power" question confuses me because my answer is "both"... obviously. But it would be more important to me that my car continues to pull like a freight train all the way through redline than in the beginning off the line and dies up top. Like I said, I'd be roll racing from maybe 40-50 and downshift to be in the powerband, maybe pull to 140 at most. (Don't worry, I forgot to mention the car has upgraded z06 brakes... Haha)
But, during that pull I want to be able to rip a hole in spacetime and feel like my intestines are about to come out a hole where the sun doesn't shine.

Anyway... If a custom cam is the best route to go then I will shell out the extra cash... There's just a lot of questions on the questionnaires (Pat G) about springs, what rpm I'll rev to, etc. and what not that I don't have figured out just yet. I always thought that what cam you used would determine what springs you need and best valve train geometry. The main reason I was looking at the g5x3 was because it's a proven performer and LG is right in my backyard since I live in Dallas so I could have them tune it. Being that it's their cam I figured they'd know how to tune it best.

 

With the ti valves and upgraded valvetrain and rod bolts you should be good up to ~7000 rpms.
I don't recommend it but I've pushed the SBE to 7500 several times in competition(several videos floating around) but would be comfortable to 7000 rpms occasionally as mentioned. Just don't rev there all the time and maybe keep it around 6600 when you are not racing.
Also, I have a max effort custom cam NIB for a 346 that I spec'd out with some high rpm spring to match. These are singles but made for the high rpm and have been tested against the best comp dual springs. I'm thinking these items may be perfect for you. Pm me if you are interested. My car right now is a cam-only c5z that runs strong with unported 243 heads and have several motors all n/a that focus on high rpm.

 

I was mainly thinking about upgrading the top end only. What kind of labor costs would be involved with replacing the rod bolts? I know they're pretty cheap, I think ARP has some for around $130 or so. What kind of power are you putting down with your cam and how's the drivability?

 

Probably close to 500whp on dynojet but it's a dedicated strip car now and sees little street time. I'd image a good tuner who has the time necessary with the car could make most any car driveable.

Rod bolts are extra insurance.

 

500 rwhp on a stock cube 346 with unported 243 heads? What is this black magic you speak of? haha

I might have to send you a PM in a bit here to get some info on this.

 

Tony Mamo, Brian Tooley, Pat G or Martin at Tick Performance in that order would be by list of people to call for parts and advice. None of them would likely recommend the G5X3 as you don't need that much duration on a 347 CID motor to get great acceleration and plenty of top end. You'll get best results with a cam designed around your heads and supporting mods.

 

Don't you need lash caps with the Ti valves? If so, it may mess up the rocker geometry on a stock rocker. Best to verify the need for caps and the geometry during assembly.

 

Yeah I need lash caps and when I spoke with Wegner they said I need to shim the rockers 1/1000th of an inch to get the right geometry.

 

I spoke today again with Wegner and they said that if I had them milled then it would mess with the flow numbers pretty bad because I'd be taking away the tail of the port... don't know if this is such a good idea.

 

You have to trust your head guy. I ditched factory heads 10 years ago. It worked very well, when I was NA. GL.

 

Let us know how things turn out.

 

I was just looking at buying some of the same heads, and the valves had the push in stainless caps as part of the valve already. Put a magnet on them imo. Weird the ones my buddy had would be different as they were wegners with delwest. I just didn't buy them cause I didn't want to deal with TI exhaust valves. May or may not be a long term issue but enough talk to scare me away when i have have sodium filled vales already which are within 2-3 grams.

 

Interesting... he said I'd need them if I didn't have them on there already but I haven't actually gotten into the box yet and opened them up so I'm not sure if I'll actually need them or not.

What were your concerns with the Ti exhaust valves? I hadn't heard anything bad about them before. I just figured the Ti valves are really light so they'd be a good thing to have. Plus, even if I didn't use them they're about $1600 brand new so there's definitely some resale value there if I end up using different ones. Think the Ti would be better than stainless though because they're around 15-20g lighter so I might be able to use beehive springs in my setup (not with the g5x3 cam obviously... thinking about getting a custom one spec'd now) which would give me a few hundred RPM more to play with.

 

gl.