Good Day All

Im going to replace my stock LT4 cam with either a "Hotcam" or something aftermarket. Does anyone know if you must remove the engine to do this? If so remove engine and trans at the same time? Or lower the engine as to be able to remove the Balancer?

Also if someone knows of a cam lumpy like or lumpier that will make more power than the Hotcam id like to know what it is! and who's OBD2 Tune?

Thanks, Ken

 

I did my hot cam swap with the engine in the car; nice upgrade; replaced the valve springs and seals at the same time with stock LT4 items; replaced stock LT4 timing chain set with an LT4 "extreme duty" timing chain; pricey but definitely more rugged.. It will require dropping the pan; not particularly difficult but does require some work under the car; with a basic tune up and one new catalytic converter, it passed California smog with flying colors; as to cams, the stock LT4 valve train / springs can only accommodate 0.525" lift at the valve, so don't use a cam / rocker arm combo that goes beyond that. You'll probably want to factor in the cost of a new water pump and Opti. With the pan off, I also rolled in a new set of rod and main bearings and replaced the oil pump. Oh I also replaced the oil pan with a Canton road race unit, so you can see how one thing leads to another when you start working on these cars.

 

Call LE and get a cam from him, I don't think you will gain much power from a hot cam over the stock LT4 cam. You don't have to pull the motor, but you may have to pull 1 motor mount bolt and lift the motor up.

 

Swap valve springs and have a custom hrind cam done or something more aggressive than the HotCam. That's a lot of work for minimal gain. If doing a cam headers and exhaust would be on my list as well with a solid tune.

 

I do, I have a 1971 SS Camaro, 468 13:1 2X4's 10.39@131

 

I put a hotcam in my LT4 with the engine in the car. To get the damper on and off I did have to loosen the motor mounts and lift the motor a bit. I left the motor mount nuts barely on the threads in order to make sure I didn't lift the motor too high. I too installed an extreme duty timing chain set but honestly the stock chain didn't seem all that bad with 125,000 miles. I'd still recommend doing it while you have it apart though just for peace of mind. I did a PCMForLess tune, kept my original PCM stock and just paid their charge to provide a replacement. If you're starting with a true LT4 you can get away with running all your stock valvetrain with the hotcam. A lot of people say you should replace the springs if you have a lot of miles but mine with 133,000 miles now doesn't have any problems with valve float.

As to performance improvements over the stock LT4, there definitely is some but it's not earth-shattering. I actually lost a bit of low-end torque below about 2,500 rpm. You can feel it come on the cam between 2,500 and 3,000 and then it pulls noticeably harder from there on up. The stock cam was running out of steam once you got over 6,000, the hotcam pulls strongly all the way to more than 6,500. My rev limiter is about 6,750 and I've accidentally hit it a few times.

Starting with an LT4, the hotcam is a relatively economical way to get a small bump because you can reuse a lot of the stock parts. If you want something hotter I'd probably contact Lloyd Elliot and see about having him work over your heads and provide one of his cams. You'll spend a couple grand more but you'd also probably get about 50 more hp over what the hotcam alone will provide. When it comes time to rebuild my engine I'm definitely thinking about going that way.

 

I definitely have an LT4. Im thinking going through the engine as it has 170,000 on it but then I'm not sure if it is the original for that car. It has been in there a long time as it gets really dirty under the water pump. I can't make sense out of the small numbers under the ID letters on the block ahead of cylinder #2 bank. The letters designate it the LT4 block and the heads have the LT4 stamp. It uses only 1/4 of a quart every 6,000 miles, that's right. Incredible. I may do a cylinder leakdown test. If I can throw just a camshaft at it for $250 and get 50 HP id do it then add Headers and a tune. Do a Distributor and Water Pump while im in there. Any more than that and Id probly just yank the engine and go through it. As it is id like to know if there is an aftermarket cam that would go in just as easy and yield a larger HP increase possibly a newer lobe profile design.
I want to see this car run low 13's and maintain drive ability and fuel mileage. It gets 28+ on the open road easy.

1996 OBD2 LT4 ZF6speed. Has Z51 suspension package. All bone stock right now.

 

I don't have dyno numbers but I'd guess by seat of the pants feel that I maybe picked up 20 hp over the stock LT4. The hotcam is about as radical as you can get while still retaining the stock springs. I know a lot of guys like the Comp 306 cam but you'd definitely need to replace springs to run that one. As far as drivability, the hotcam has a very mild lope to it, it's not bad at all when I get into stop-and-go traffic. Fuel mileage definitely took a hit in the stop-and-go, not so much on open highway. Stock I used to generally see around 16 in my city commute, now I'm generally around 14. Highway I used to get 28+, now I'm usually in the 26 to 28 range. Idling definitely seems to use more gas than it did when stock. Mileage is better at higher elevations but it runs much better at lower elevations. I normally have the car in Denver but occasionally take it to the Dallas/Ft. Worth area. At lower elevations my highway mileage drops to the 24 to 26 range. Haven't had it to a track yet but I think I could break into the 12s in Dallas. Denver, maybe low 14s.