I'm building a 383 fully ported LT heads w 2.02/1.60 valves, roller rockers ( comp 1.6) hooker long tubes , 37lb racetronix inj, 58 mm tb, cai, vortec elbow,and electric h20 pump and ud pulley. and soon to get tuned


I'm waiting on purchasing a cam til next week, my builder SRI out of Hastings, Michigan is looking for a bigger cam than the gm 847. what are the 383 guys running. My goal is to break into 11's and have the rear installed now which is Ford 9" w/ 3.89 gears.

thx guys for imput,

jonesy

 

You could always give Bret Bauer or Joe Overton(if he's still in the game) a call and they will hook you up with something no OTS cam can.

 

/thread

 

I really don't subscribe to all of the custom grind cam hype. Thunder Racing carries 14 LT1 grinds from Comp alone. Other manufacturers make even more. I'm sure SOMETHING out there fits the bill.

The 847 is a good cam that works well. I had it in my old 3rd gen. With an 11/1 383, AFR210 heads, Victor Jr/carb, shorty 1 3/4" headers, and full weight, it ran 11.09 at 122.5 all motor. Breaking into the 11's shouldn't be a challenge at all.

That said, Comp's new XFI 242/248-113 looks very promising. It has similar seat timing to the 847, but alot more area under the curve. It should make more power, but idle the same and have the same response and low-end. However, with the XFI lobes, you have to run alot of spring rate because of the quick ramps.

Mike

 

thanks I'll lookit up

 

i think if he's got some flow numbers and provides the proper information to some of the known cam grinders on this site....he won't be unhappy.
these guys have been making a living at making cams specifically for custom setups, i think they can get pretty darn close to making a cam that's gonna make the most power from your setup.
and they don't cost anymore than a cam from any of your other companies....so my question is...why not go with somthing that is proven to make more power?

 

Several of the "cam experts" don't know as much as they think they do. Even if you find one that does know alot, I bet there's an off-the-shelf that will match or beat it.

Remember Stumpy's 440 rwhp stock bottom end, stock ported head, stock ported intake LT1? Let me just say that the XFI 242/248 is VERY close to his spec's.

Mike

 

Mike,

The problem is you don't know as much as you think you do about cams. You don't have to subscribe to it that guys who spec out camshafts know more than you about it, but from what I have read on your thoughts on the subject you are WAY out in left field about what actually works. Going to the bottom of page 168 in the Comp Cams catalog and saying, yeah this one is the biggest one it will work, doesn't ACUTALLY work out so well.

I don't know how someone can arbitrialily recomend the XFI 242/248-113 to a guy when he doesn't know the stall, weight, rear end gear, use of the car, compression, head specs etc.... of the guys combination. You even say it looks "promising" reason being that you have never SEEN it work yet. Problem is I know what that cam will do and it will be gutless in the low and midrange, and fall on it's face at the top end (over 6000rpm) where the duration and valve events will want to work the best but can't because your not going to be able to control the valves correctly.

This bottom of the page cam selection is dangerous ****. Let alone YOU not knowing how the valve control will be with those lobes, and forget any idea of valve curtain area for the RPM range and cubes that the guy has and needs, or what overlap will work the best in terms of power. Let's just throw the cam on a 112-114 LSA and throw duration at it untill it looks promising and call it a day.

Sorry to jump on your case, but there is another side to the story here other than pick the biggest cam you can and throw it in there.

Bret

 

847 would be a serious baby cam for a 383, definitely get a custom grind if your staying hydraulic.

 

Nothing wrong with "baby cams" either....Just because they are big doesn't necessarily mean they are better...I've sent many big cams home with my weenie cam...I'm in the 22X/23X range with mine and it pulls everywhere and I don't have to spin the motor passed 6300 to do it...

I know Bret's been riding me to get back to the track with my new mods, and I will when the weather falls below 90deg in the shade....Initial tests suggest 11.teens to 20s in good weather/track prep with a weenie cam that gets 20 mpg highway and can be daily driven with ease...

--Alan

 

Bret, who pee'd in your Cherios this morning? I wasn't referring to you, but maybe I should have. . .

I have alot more actual dyno experience with cam design than you may realize. Are the XFI lobes hard to control over 6000? Yes. Can you set up the valvetrain so that they are controlled over 6000? Absolutely!

As far as the weight, gear, converter, and compression go, the base case assumption presented in the original question was that the 847 cam is good. Based on that, the seat event timing of the XFI 242/248 is very simililar to the 847, but with a few more years of technology and, thus, area under the curve. You're crazy if you think that I simply "picked the biggest cam" I could. If that were the case, then I most certainly would have recommended something north of 260 @ .050".

I just realized the root of the insults. I recommended against a custom cam. Bret makes money off of custom cams. 'Nuff said.

Mike

 

...It's all in the total combination. What do you want to accomplish with the car? I went with Joe Overton and am very happy with the results. As Bret said above, be careful with "bottom of the page" large-by-huge cams...

--Alan

 

I'm using the 847 with 1.6s and am pretty happy with it, I just want more compression (and plan on rectifying that some day), Of course it's my own fault to start with only 10:1 compression, but it still knocks down mid 11 second E.Ts with the shifter in drive. (best so far a month ago was an 11.52 @ 119 mph)

 

Now from a guy who knows nothin' about cams:

IMHO, a 383/396 etc. is still a SBC. Overcaming a SBC without going with big flow heads, balanced bottom, forged crank, etc. ---i.e.,putting some serious work and do re me into the project---in addition to beefing up the rear end, getting rid of a ton of weight, etc. is like putting a bottle rocket up a camel's ***---he might go like hell for ways, but he's not going to like it and don't expect him to give you all that of good a service in the future.

Perhaps we ought to have (2) Sections, 1 for cars that you can actually drive and 1 for those that are flat-out racing machines.

While a BBC may handle bigger cams where you don't have to wind them up so high, a SBC, sans the proper set up will most likely give you lousy power down low in the RPMs which in turn will cause you to really wind it up to the point that you threaten the integrity of your crank case and everything within.

Having said this about that, I don't recall seeing any major differences in performance between a relatively mild cam in a good combination and a Big A$$ cam with nothing but BIG stuff i.e, BIG TB, BIG INJECTORS, HUGE CONVERTORS, etc,--in a NA engine.JMHO

 

I about died on the camel analogy.