Its an LT4 hot cam.. The cam was put in a factory car.. The LT4.. They put that small cam in as a daily driver, street car. also with emissions in mind.. The cam is garbage.. with a 383.. I would go GM847.. Thats the way i was going.. I actually still have that BRAND new motor for sale.. fully forged, gm847 and a LT4 heavy duty timing chain.. 847 is what i paired it up with.. Its a hydraullic cam, your dads car is probably flat tappet. There is a big difference.. On hydraulic cams, the spring pressure can only be so much because of the hydrualic lifters limiting you.. The cams that are the most extreme are still fairly streetable.. Its a hydraulic system, what you should be most concentrated about is what cam will work best with your setup and not be worried about driveability.. most of the cams are streetable. except a few may discomfort someone more then the next person. get rid of it..

 

The cam isnt the problem...I bet the heads and tune are. Light port work on stock heads wont help. You need a fully ported set of heads to help it breathe. Guys with the hotcam and 383's with ported heads are making anywhere from 370-390rwhp. Go to fbody.com and check out "blackscreaminmachine". He is putting down close to 390rwhp thru an auto.
Who did the heads?
Just for reference i put down 351rwhp/340rwtq with a homeported heads, XE230/236, and mail order tune. I doubt the injectors are that big a problem. I made 383rwhp/353rwtq with 113% DC on stockers.

I still bet tuning A/F and timing and the heads are the issue.

 

The LT-4 Hot Cam is NOT the LT-4 stock cam. The LT-4 Hot Cam was developed by GM Performance Parts for the showroom stock racing series. It a road racing cam, designed to pull a heavy car out of a corner. It IS a higher RPM cam...power with it peaks around 6000RPM. When you install one in an LT-1 or LT-4 you can spin the engine to 6400 and it still has some left. The stock LT-4 cam has like 0.47" lift with a 204' duration on a 115' LSA. The Hot Cam has 0.525" lift with a 219' duration on a 112 LSA.

People running the Hot Cam in an LT-1 or LT-4 are putting out ~ 320-330rwhp. Obviously the cam is not the problem with his motor. Something else is wrong. With a stock LT-1 cam the 383 should be putting out ~ 300rwhp. I would look at the compression, ignition timing, and also your fuel mixture. If the stock LT-1 injectors are good to 350rwhp in a 350, then they're good for 350rwhp in a 383.

The other thing is make sure you really put in the Hot Cam, and not just the stock LT-4 cam.

-Dave C. '97 Z28

 

Just wanted to point out that there is no such thing as an "LT-4 HOT CAM". There is the LT-4 cam which was used in the LT-4 Vette motors, and then there is the HOT CAM. The HOT CAM was never used in a production motor. It is an aftermarket cam sold by GM Performance Parts. It is quite a bit bigger than the LT-4 cam, especially in the duration department. However, I believe that the HOT CAM can still pass emissions in most states.

Sorry, I just had to jump in here. I see a lot of people saying the HOT CAM is the same thing as the LT-4 cam, and I don't want anyone getting confused.


Edit......Beat me to it......

 

Well I think the pistons were a flat top kind(keith black). The pistons were included in a 383 kit. The heads were re-done with work done to them which was suppose to be a 5-angle valve job and porting. I dont know if they did anything to the bowl, but wouldnt that be good in this case to keep the compression up? As for the timing the computer has yet to be re-done. They will dyno tune it and see how it stands after a dyno tune. I just cant see where they will pull 30-40 rwhp from a 300 rwhp baseline un-tuned run. Maybe the timing is off but i can tell you that the idle was good as well as the general smoothness of the motor. The guy at norris motorsports said that when he did the dyno pulls he noticed the A/F ratio was bad. Maybe the injectors need to be replaced soo the ratio stays richer at higher rpm's? I may be able to throw in a cc306 if i can convince my father that this whole $7000 project is wasting money if the motor is making only 300 rwhp. I dont know how much a tune and injectors can get out of a 300rwhp pass. I bought the whole kit for the HOTCAM so i got all the valvetrain goodies too. Would it be better to run the cc306 in this motor or would it be a waste of my time to do it beacuse of the heads. If i put in the cc306 then i will need the injecors and the tune with it. What could the RWHP reach at that point??

 

I bet you could definitely pick up 30-40rwhp if you have a stock 350ci tune in it. That will put you at 330-340rwhp..still under achieving because of the heads. You dont worry about compression when porting the heads. Now if he was doing the combustion chamber (where the valves are) then that would change compression. You need fully ported maxxed out heads.

 

I have a set for sale.. 900.. Ill send you pics if you want.

 

Do you really think that the stock tune will hold back 30-40 RWHP? If soo I can live with that. The next thing i will invest in when i get on my feet with the whole insurance and gas money thing will be used performance heads and a cc306 or GM847 with a dyno tune. But for now if i get the car sittin at 330-340 RWHP then I will be one happy 16 year old. The torque will probably be sitting about 20 ft/lbs ahead of that making it a 330RWHP/ 350RWTQ. I think if this upper RPM lean condition remains then I will go to a bigger injector. Any more speculation on how the tune will help me out? When he started the car it idled perfect and ran smooth. What exactly will they do when they dyno tune it? Thanks, Brian

 

Sorry to take this post elsewhere but... whats the difference between a CC306 and a XE227/233? Comp Cam means what? XE means what? Sorry again...