Markbo

As some of you may remember, it's a long story, but I am finally seeing some progress. I am getting my stage II heads back from GTP after testing and re-porting them after the disappointing results. These are going on a built 396 stroker in a 96 T/A with OBD l. I only have a faxed graph as yet, so I will give you the numbers as close as I can see them:

Flow @ lift .3 .4 .5 .6
Intake 208 249 275 292
Exhaust 159 179 199 212

I have cc numbers for the chambers if that would help, and I will of course have them flowed independently, but how do these figures look for stage II's on a stroker motor?

I also have to figure out what cam to use to match these heads.
My criteria are: This is for a weekend only fun car that must be able to run A/C in HOT weather and heavy traffic, on pump gas. I do NOT want any vacuum or surging issues, i.e. my girlfriend must be able to drive this car if she needs too.

I already have a dual 75 shot wet system installed that will be used very, very infrequently, so I prefer to maximize for power without it, rather than sacrifice daily power for the nitrous.

What about these cam choices?
1. CC236-242-112 (.558-.576 lift)
2. CC248-250-114 (.576-.600)
Of course GTP is suggesting their GTP 6.

Any pros-cons, advice anyone can offer would be very much appreciated. Also, what springs would you recommend, using 1.6rr's? What are in there are too weak and he will upgrade them - I just have to know to what.

Here is as short a list as I can think of the pertinent mods that I can think of.

Patterson Motorsports built 396 corvette block (4 bolt mains) stroker motor with M6 & Moser rear end with 3.73 gears
OBD I w/ Fastchips tuning (just an initial OBD 1 tune – a dyno tune will have to be done after cam installation) on all forged drivetrain- Callies crank, Eagle rods, Clevite bearings & JE Pistons
Note: compression ratio calculated to 11.8:1
GTP stage II heads & ported intake
Comp cams stud girdle kit & AFR hydra rev kit (for ‘insurance’ really, but high revving should not be a problem)
Bullet proof Comp cams valve train (all came from GTP with the heads-magnum roller rockers, dual springs, etc, etc)
SVO 30# injectors
Extreme duty timing chain
Hooker ceramic coated long tube headers with Mufflex off road Y pipe & SLP dual/dual catback
58mm AS&M TB
160 deg Thermostat
WS6 factory hood w/ SLP airbox kit & K&N Filter
MSD 6AL & Timing retard, Taylor 10mm wires, NGK's

Any advice you 396 guys can give me on the heads, cam and springs would be very much appreciated. Once it's all back together, the first order of business will of course be to get it dyno tuned, but I have to pick the last couple of components first.

My usage will be as a weekend street car. Maybe occasional auto cross track and strip use, but I am most interested in just having a really fast street car. Very high speed is not a goal. I think I can hit more than I need to no matter what I choose now.

Oustanding handling and maximum grunt from 0 to 100 is what I am interested in. I have built the chassis and suspention for handling - or as someone once put it on this board 'you have built an autocross car with a drag strip engine'. I think that is a very good definition of a seriously badass street car.

If you need more information, just ask. I can post my entire sig/list of mods if you think it will help or answer any question you need answered to help me make these last couple of decisions.

Many thanks in advance to anyone who can help
Mark

96speed

Hey Mark,

I had success with the GTP6 cam. It would likely work well with your combo (more compresion, cubes, and gears - my car has none of those). A plain jane GM847 or a cc306 would be fine. Those cams make power, although I don't have any personal experience with either. That 248/250 is probably not what you want.

Also, I hate to say it, but if those heads flow 290, you are a lucky guy. Do yourself a favor and challenge Craig to guarantee his heads against another flowbench. If he gets defensive, you know what that means...

btw...You will get better help in the LT1tech section.

Good luck.
Ryan

OldSStroker

How about having the cam professionally designed specifically for the engine and your requirements? Your driveability requirements are critical to the design. I wouldn't expect the design to be free unless you buy the cam and other related valvetrain parts (if needed) from the designer.

Various folks have been mentioned on these forums who could do the job.

Good luck.

rskrause

Good advice! A buck fifty or so spent here may well be money very well spent.

The #2 cam you mentioned is a huge cam for an LT1. It also doesn't have enough split between the exhaust and intake durations. You have ~72% E/I flow ratio and need to compensate for this, especially since you are going to run some nitrous. The first cam is more reasonable on duration, but could also use a bigger exhaust lobe. I don't know the specs of the GTP6 so can't comment on it.

Bret Bauer is a guy you might consult about a custom cam.

Rich Krause

kmook

Yeah that #2 cam definately wont be girlfriend compatable I'd agree with the above and get something truely custom made for your taste by having someone good sit down and take the time to make you what you need.

Also this really should be discussed in LT1 Tech as mentioned above. Thanks.

Markbo

Guys, thanks very much. On advice of Injuneer and Rich, I reposted this here on Advance Tech and already have a similar thread on LT1 tech, but nothing on that one yet.

Just for easy reference here is a link to my original thread:
http://web.camaross.com/forums/show...threadid=180913

The two cams referenced above were suggested by Comp cams direct and a local shop. I would much, much prefer a custom grind, but frankly didn't know who to go to for that. I am in touch now with Bret.

Thanks again
Mark

got_hp?

brett will definetly be a great choice for a custom cam!

thunder and futral also do great with custom cams.

96speed

Who is going fast with one of Brett's cams?

I'd try Cam Motions personally.
Ryan

SStrokerAce

Ryan,

Without looking like an *** here, let me try an answer this and not give any customers names away.

Our normal cam designs are not what the average guy runs. Not a huge amount of stock bottom end, stock headed, cam only cars. Not a huge amount of stock bottom end, ported LT1 head cars. Mostly we work on the odd combinations, strokers, different intake manifolds, carbed setups, blown motors things where you can't go and get a off the shelf cam from GTP or Combo. The cars they are in are anywere from weekend cruisers to race only.

For the guys who do run a "standard" cam from us they are not looking for the 847, 242/248, biggest cam you can get in a stock bottom end car. They are looking for cams that still drive decently, don't have bad road manners and make HP and midrange TQ. 340rwhp out of a cam only car is not that hard to do, to get the extra TQ in there with the cam is the key. I would rather see more TQ at 4500-5500 than get an extra 5rwhp for bragging rights to sell more cams, doesn't really make sense to make cars slower for bragging rights.

Now now to put down Cam Motions, but the technology difference in manufacturing from Cam Motions to someplace like Comp or Crane is pretty big. The big cam companies have more R&D money in their lobe designers and spintron equipment. They also have more accurate cam grinders since they use Okuma CNC machines vs. traditional manually operated cam grinders. Not to say the old machines are bad, every Nextel Cup cam that comes out of Comp is done on a old school machine, but for Roller cams the Okuma is the way to go for spec accuracy, speed and lobe profile accuracy. This might be a reason why most of the NASCAR fields are filled with Comp Cams camshafts in their motors.

FWIW we use Comp to grind our custom cams, we use our own software and knoledge to pick out the right cam for the customer.

BreT

kmook

I'd definetly give Brettt a try on a custom cam if I already didnt have something sitting in my house. It is good to have someone knowledgable be able to sit down and spend the time needed. Even if there wasn't anyone on the board with a cam from him... remember there are TONS of fast people in the Fbod community that aren't on this board.

SStrokerAce

Thanks Kenn Moook ;-)

96speed

Bret ,

I understand your position. However, I haven't heard any numbers (I don't need names) of anything except Matt's - His dyno and trap speeds don't seem to add, IMO - that's another thread tho .

I'm not trying to make a cheap shot at you; just anxious to see some numbers from your combos.

I'm not doing anything crazy or going fast, so my opinion counts for squat .

Ryan

SStrokerAce

Ryan,

Yeah there are not many public numbers out there, which is not my choice but I don't go touting anything, that's for the customers to do. In fact a lot of cams done over the last few months have not really even hit the road yet.

With Matt's car it gets me too because that thing was one hell of a low budget motor and the cam was ment to make power at a low RPM (6000rpm), I've driven the car at the strip and it's goes well until a mis develops at the high end and still traps the same speed. There are some tuing issues and other things going on there with that thing but I'm pretty sure we will get them worked out and tweak that thing a little bit more. There are some bugs to be worked out definately but for now a 100+gain from his new motor and well over a second reduction in ET is a good place to start.

I don't take that one as a cheap shot, something is not running right there so that needs to get cleared up. I have a few motors in the shop and some cams out there that I am waiting for the numbers to come back from, but even cams I have speced out for guys before we sold them still put down good numbers for what the combination.

Bret

MPM IV

Great post. I'm in an almost identical position. I'm currently running a cc306, and when I upgraded my heads I actually lost about 15rwhp. I'm currently making right around 385 rwhp. I think I'll be giving Bret a call once I work out a couple of other issues. Thans for the info.
Malcolm

Markbo

Malcolm, for what it's worth, the cam I was running previously was 224/236, .536/.558 w/ 1.6rrs and 112 LSA.

I got a dynoed best right around 380HP. I thought I should be making much more than that, thus this latest excursion. It did allow me to find out that my heads were not flowing what they were supposed to be though!

After so much time, effort and money, the thing that I have lost the most of is trust. Getting completely hosed by two shops in Houston, not getting what I pay for, being without my car for 3 years. This is the stupidest hobby I have ever had!

Well... except for wimmen... and guns... there's a couple of money pits for you!