gm847??
12-05-2008, 10:52 AM
#21
Cause everything I have researched on that cam on this very site and others, has said that is a big lift cam with upper rpm power production. High rpm needs heads that flow. Stock heads dont flow well in upper rpms with bigger cams. Everybody knows heads are what makes the engine, so why overcam the car if your heads are stock?
I dont have a dyno graph and hard info to display on a chart for you sorry. If you have been successful that is great, I have not heard much about anybody running 11's with cam only 847. Are you like a special case?
I dont have a dyno graph and hard info to display on a chart for you sorry. If you have been successful that is great, I have not heard much about anybody running 11's with cam only 847. Are you like a special case?
Prove me wrong. I've been asking everybody for months and not a single one can do it.
12-05-2008, 11:31 AM
#22
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Show a single thread then. There's nothing out there showing what you are saying except people like you repeating what they read about it being too big! Nobody has shown proof of this. Sure you'll make more power with bigger heads, sure you will then need a built bottom end to rev it where it needs to. With stock heads it peaks at 58-6000. Sounds like the stock bottom end can easily handle it's rpm range with stock heads. And with stock heads not only does it peak higher, but there's more power UNDER THE CURVE too! You will want a higher stall in an auto and lower gears in a manual. But with stock heads and bottom end it out performs all smaller cams minus custom ones.
Prove me wrong. I've been asking everybody for months and not a single one can do it.
Prove me wrong. I've been asking everybody for months and not a single one can do it.
GM12370847 --- 234@ .539/ 242@ .558 (1.5RR)--- 112 LSA -2000-- 6800
Based on specs 6800 is higher than what a stock shortblock should go on a reg basis. (dont know why stock would peak earlier)
Not only that but the guy wants to put 1.6 in to add lift when the cam is already big for the heads.
Your asking me questions like I am a performance shop that has funds to do back to back testing. Like I said if it worked for you great, keep on preaching the proof.
Here is a thread where Bret already talked with you about why it is peaking early. early.http://www.ls1lt1.com/forum/showthre...t=14317&page=5
Last edited by 97LT1; 12-05-2008 at 11:44 AM.
12-05-2008, 11:59 AM
#23
Yes, he said that. But I also showed more than one dyno graph showing peaks all in the same range. And they were running high 11s cam only.
So sure maybe one was down, but they couldn't ALL be having something "screwy" with the valvetrain.
Bret also showed a custom cam of his overlapped with the 847 and the 847 was barely lower across the board, but it peaked higher and later... but still at 5800 rpms... and still made 350+ hp.
So sure maybe one was down, but they couldn't ALL be having something "screwy" with the valvetrain.
Bret also showed a custom cam of his overlapped with the 847 and the 847 was barely lower across the board, but it peaked higher and later... but still at 5800 rpms... and still made 350+ hp.
12-05-2008, 12:24 PM
#25
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Yes, he said that. But I also showed more than one dyno graph showing peaks all in the same range. And they were running high 11s cam only.
So sure maybe one was down, but they couldn't ALL be having something "screwy" with the valvetrain.
Bret also showed a custom cam of his overlapped with the 847 and the 847 was barely lower across the board, but it peaked higher and later... but still at 5800 rpms... and still made 350+ hp.
So sure maybe one was down, but they couldn't ALL be having something "screwy" with the valvetrain.
Bret also showed a custom cam of his overlapped with the 847 and the 847 was barely lower across the board, but it peaked higher and later... but still at 5800 rpms... and still made 350+ hp.
12-05-2008, 04:21 PM
#31
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Word of advice. Dont stager the rockers. That just my opinion. Why not get max lift out of the cam if possible? So use 1.6 all the way across. A friend of mine went 12.2 with a full weight STOCK HEADS 97 trans am 3:42 gear drag radial STREET car. The cam works. Its a good cam if you can get your car dialed in which takes time.
12-05-2008, 07:18 PM
#32
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well all I can say is that I am surprised, and glad to see the cam works well with stock heads. I guess I have been misinformed in the past, and glad to see there are good results with the cam. I just dont understand why the cam functions so well under lower than advertised.
12-05-2008, 08:34 PM
#33
I say go for it, if you dont mind the way it drives and RPM capability do it.
Im planning to use either the 847 or 306 when I rebuild the bottom end on stock heads.
Sure it would run better on ported heads, but that goes for anything.
Small blocks like to rev, I say let them.
Im planning to use either the 847 or 306 when I rebuild the bottom end on stock heads.
Sure it would run better on ported heads, but that goes for anything.
Small blocks like to rev, I say let them.
12-05-2008, 10:50 PM
#35
I will tell you that I have a 94 Z with all the bolton goodies, 3.73 gear, 3200 stall, no emissions and I did install that cam and was some what disappointed. Yes I too have stock heads and like everyone was telling me that it was just too big. To me if felt doggy until midrange then took off like crazy but then it was shifting. It didn't even sound like the other cars that had the same cam with head work. I shortly took it out and had a custom ground one made. It sounded better and was much faster. Oh another thing, the damn car was surging at stoplights which became annoying. Couldn't get it to tune and was driving Brian from PCM4less crazy. He told me I just needed more flow out of the heads. This is just my opinion and all I will say is good luck and have fun.
12-05-2008, 10:58 PM
#36
well my tune from ion@madz28 is dead on. Mabey its ure tune that garbage cause my car runs like a raped ape and has tons of low end. IMO CM for less is a mass roduction tune place that does every car under the sun, Ion on the other hand did a LOT of lt1s and knws them very well, maby thats why my car runs soo good.
12-05-2008, 11:03 PM
#37
This cam can work well if you have the correct supporting mods and are willing to rev the motor to near the pcm limit. You obviously have your car setup for this cam, and your 2900lb car is helping it greatly as well. But to the average person there are a lot better choices out there if he wants an off the shelf cam.
12-06-2008, 03:30 AM
#38
This cam can work well if you have the correct supporting mods and are willing to rev the motor to near the pcm limit. You obviously have your car setup for this cam, and your 2900lb car is helping it greatly as well. But to the average person there are a lot better choices out there if he wants an off the shelf cam.
i totally agree with you. I wanted to do a custom cam but nobody got back to me for weeks so i bought this one. It all depends what you want to do with the car. Mine is my race car so i bought this cam with the intention of really beating on my car. Ifi ts a DD and just to do sick holeshots etc. then buy a smaller one where the power comes in sooner.
12-06-2008, 03:45 AM
#39
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Summit or jegs id look. I do not think id use a gm847 on a stock car.