Hey all,
MY 96 lt4 6SPD is due for some mods this winter. I just installed a vortec ram air intake system and a 52 mm throttle body, and am thinking about a cam swap for xmas.
The car has 411 gears, and loves to rev. Is the LT4 hot cam the way to go??
This is not my daily driver and HP is the most important.
What do you guys think??? :cheers:

 

I'm sure there are more performance cams out there, but they my not be too street friendly.

 

If you don't care about drivability then the hotcam is a bit mild for big HP.
I would think more along the lines of a CC 306 or mabey even bigger for big HP. Are you going to do any thing to the heads? You will need new springs and you should think about porting them to get the most out of the cam. If you go with anything bigger then a hot cam you may find out how much lift your LT4 RR can take as well. The LT4 uses the non-adj. rockers and the studs are kind of weak IMHO. I am using the LT4 R/R and studs on my LT1 but hate the fact they are non-Adj.

Good luck and there are a lot of ponies in the LT4 just waiting to come out and play.

 

For the price, you can't beat the GMPP Hot Cam for the LT4.

My friend Jim "96GS#007" Mason revs his LT4 to 6800 rpms on a regular basis with the Hot Cam. Stock heads and a few bolt-ons he is running 342 rwhp with this cam.

 

:iagree: For a replacement on an engine with stock heads its a great cam that makes good usable HP. Going with a CC306 is going to require different springs and that means possible head work to fit the springs. Plus the CC306 is not a everyday driver type cam. Sorry but I have to disagree with the statement that the LT4 studs are "weak". They are in fact 10mm studs which are a bit bigger than the old standard 3/8 or .375" studs making them actually a little stronger.

It is however very popular amoungst the F body crowd so I am sure I would get a lot of arguments about streetability. However the Hot cam is the best bang for the buck when used in a near stock application. It provides good all around power increase with the LT4 heads as they are. Additional porting also enhances power, plus this cam easily passes emissions with some minor tweaking. With a 306 you might squeak by with lots of tuning, but then again you would most likely have to return to a previous calibration to get your power back.

If you do decide with the Hot cam, it is recommended that you replace the springs. Even though you have an LT4 getting the springs replaced is a low buck item and only takes another couple hours of time to do. It is especially recommended if you have over 50k miles on the car.


[Modified by tjwong, 8:02 PM 11/30/2003]

 

The LT4 studs may be 10MM at the base but they taper way smaller then 3/8 where the nut goes on making them much weaker then the std. 3/8 stud.

As far as the hot cam yes it is a good cam for a daily driver but he said drivability was not an isue and he was looking for HP. I woud replace the springs no mater what cam I installed because the LT4 stock springs are marginal at best even for the Hotcam. As far as retuning the ECM yes it would be best if it was reprogramed if you instal an agresive cam but then again you will get more out of it if you reprogram for the hotcam as well. Look I have the hotcam installed in my car with the LT4 R/R and ported heads but if I was looking for the most HP with only reworking the heads and a stock bottom end and drivability was not a concern the the Hotcam would not be the best selection IMO. It all depends on the HP you are looking to get and if you plan on doing some head work. There are other cams out there and some of them make more power then the Hotcam.

 

I have had very good results with my crane 109831. 335 rwhp and 328 rwtq with stock lt1 heads. I would guess this would be good for at least 350 rwhp on stock lt4 heads. It has a little more ***** to it than the hot cam but is very drivable. On a 96 it would require the longer dowel which comes seperate with the cam.

 

Gotta throw the :bs: on this one. Here is a pic of the two studs in question from when I swapped in my ProMagnum roller rockers...



The OEM LT4 10mm stud is clearly larger except for the threaded area as mentioned above. The 10mm measurement is associated with the body of the stud, not the threads. All side forces from the rocker are transferred to the body of the stud (where it's 10mm) not the threaded area.

 

My gut feel is that the CC306 is too big of a cam for a street car. I was cam shopping for my 383, and was told this cam would not be good at idle for power brakes or using the A/C. You will definitely need new springs for that cam. Take a look at the CC305, or what I ended up going with for my 383 is a 224/230 cam (p/n 07-503-8) - sorta inbetween the 305 and 306. You will probably need new springs for either of those cams too.

edit: oops, wrong duration


[Modified by Jeff Hickman, 12:10 PM 12/2/2003]

 

I waited until the pump went before tearing into the cam. I then replaced the opti, cam, pump, chain. I only got 316hp at the rear with corsas and cam. I then put on the long tubes, random cats, 52mm, and slp intake. I am happy! see sig.

 

You made my point with the pic.
Look at the area of the retaining nut and see how small it is.
The stud is only as strong as its weakest point and I have seen the LT4 studs broke at the nut, so call BS if you want but it can fail with larger cams.
The rocker does have stress from side to side but the stress is also up and down due to the nature of the valve train.


[Modified by 84LT1, 10:24 AM 12/1/2003]

 

Thats the key to what you meant. Using the stock 10mm studs are OK for their intended purpose. Using them with a Hot cam or similar cam is fine as well. However when a larger cam is used that require substaintially higher spring rates then a change in parts is a smart move. There are lots of stock and mildly modified LT4's out there running 6500 RPM+ and as far as I know I have not seen any stud related failures. I am not running the 10mm studs but rather a set of ARP 7/16 studs in my car. But I am also running higher spring rates and a considerably larger carm with aftermarket AFR heads.

The original post wanted a cam suggestion for the most HP and drivability was not an issue. If he was to go with the 306 or a similar cam. He is going to have to modify his heads for the correct springs. Know that, the end user should of course upgrade to high strength studs such as ARPs or others.


[Modified by tjwong, 1:43 PM 12/1/2003]

 

HOT cam all the way.

Slides right in with your stock parts including the stock program. You may get some slight shudder/herky/jerky at lower speeds and idling along with it though.

I ran this combination for 10,000 miles except with stock 3.45's. Gained 26 RWHP with this the only HP mod. Not bad at all for 180 buck camshaft.

Want more-try a GM847 cam or a solid roller.

All depends on your definition for most power....:)

 

Oooo! Oooo! Question. The "Hot Cam" that is such a hot topic, I went to my local Chevy dealer and the parts guy found an "LT4 Hot Cam Kit" but it reads as though it's meant for someone wishing to upgrade their LT1 towards the LT4...as if it's the same cam as the LT4. Is the Hot Cam an actual GM part? Did it have another stock application? And now that you brought it up, is the GM847 cam pretty compatible with a "relatively" stock LT4? (GM847 the actual part number?). thanks and sorry if this is an age old question, just getting into possible upgrades. :cheers:


[Modified by OneRedLT4, 5:56 PM 12/1/2003]

 

Yes, you can get just the cam. GM p/n 24502586

 

If you want to stay streetable with minor mods Hot Cam is excellent choice. If hp is most important , and especially if you do head work or will in the future , more cam may be a good idea. The GM 847 mentioned is very similar on paper to the CC 306 mentioned earlier. Both are VERY aggressive hydrolic roller cams and the potential of either one will NOT be tapped without working the heads. BUT .....if you want over 400 rwhp these will get you there easily with some heads/valvetrain, headers, intake tune etc.

 

Do the LT-4 Studs have to be installed without guide plates? Lets say you had your heads cut with guide plates installed for whatever reason, will the LT-4 studs work with guide plates?

 

The LT4 studs are specific to the LT4 OEM rockers that are non-adjustable. If you machine the cylinder head or use a camshaft other than an OEM LT4 or HOT cam I think you run a big risk of not having the correct lifter preload.

Set of Crane/CC adjustable rockers is the way to go. The now offer self aligning or non self aligning...

26 RWHP-dyno proven...HOT cam works very well-nice lope and pulls to 6500+ rpm. Hard to beat a cheaper modification.

:D

 

No, the actual P/N is 12370847 (the 847 being the last 3 digits of the P/N). Specs are 234/242 (int/exh) duration at .050 and .539"/.558" (int/exh) lift at the valve with 1.5 rockers on a 112 centerline. VERY aggressive! No good for stock LT4 springs so keep that in mind not to mention that the stock LT4 1.6 rockers will bump the lift even more.

GM developed the LT4 Hot Cam for a specific reason - to be used in an LT4. Lobe design was centered around maximizing the power of an LT4 without compromising driveability. Guess what, GM engineers have a HUGE budget and they don't settle for adequate. It's simple, the cam just works. -Jeff

 

the LT4 production cam is basically the exact same as the 96 LT1 cam. the difference is nil. I always assumed the LT4 production cam was a "performance" cam ... until I reviewed the specs.

also if you do a cam, the odds of you spining a bearing are 100 fold higher.
(for whatever reason)