Just getting ready to start modding and I'm planning on doing cai, headers and heads. Curious if I'm better off buying different heads or porting stock heads. Want a mild to heavy cam in the future...

 

If you know someone that has experience porting 3800 heads then go for it but if not then I would buy. They can be messed up very easily if you don't know what your doing.

 

If I remember right, the OP has an ls4.

If that's the case, don't waste your money on heads, especially since it sounds like you're pretty stock. The ls4 already has the 243 heads just like the ls6. Those engines made nearly 100 more hp from the factory with these same heads, so they aren't the restriction in the system. What's worse is that a good port job is pretty expensive and full aftermarket heads are very expensive. I've just seen a few people personally that spent $1k+ and all that labor for virtually no gains.

IMO, your starting point should be the headers and the intake manifold. Headers are a simple bolt on that will help support future growth and the stock intake manifold is one of the worst ever used on an LS due to the D shape over the opsu. There are plenty of threads on the net about how to swap on a different manifold.

A cam is also a great idea for power, even with stock heads. However even though bang for the buck is great, the labor is the killer. As far as I know, you have to drop the engine to do it. Also keep in mind that if you go really big, you should really change converters to match. Luckily the stock converter is pretty loose from the factory, so it'll work fine with most normal sized cams.

One other thing I always tell people to consider when starting to mod an ls4- add up all the cost and labor for what you realistically want to do, and then compare that to the power and price of a turbo kit. If you're looking at headers, heads, cam, an intake, and a converter, you're already getting very close to the price of a turbo, and youll never be making the 500 or so wheel horsepower that a turbo would. You'd need those mods on an ls3 to get that kind of power NA.

Also, the turbo would be far easier to install and would drive a ton better.

 

Yea your right. His is a 7th gen. Mixture of being tired and reading fast while at work. In this case I agree with bumpin. You don't need heads for a while. Also keep in mind about the weak transmission that's in there if you start making a lot of power it's gonna need upgraded as well

 

Thanks for the info guys. I've contemplated about the whole turbo thing myself. My only concern with that is that I'd have to drop quite the penny all at once as opposed to modding bits at a time. This is the downfall of getting rid of the 3800 and getting an ls4 lol thanks again guys!

 

That makes sense. I'd try doing the headers and intake manifold first then. You won't be able to use the headers with a turbo, but you could resell them pretty easily if you went that route. The intake will still benefit you either route you choose.

Then when you get ready to do heads/cam/converter that's a good point to make the decision one way or the other.

Honestly, if a cam could be done in the car on the ls4, it would be so much more popular, it's just such a killer if you have to drop the engine.

 

with mine I have a v6 had my local speed shop make a set of headers for mine they do a lot for the sheriffs that have the impalas with the same engine and trans I have. the only thing that differs to those cars and mine. is that mine was suppose to be a undercover car so pretty much the computer already had a tune put in from the factory. the only thing I changed out when I had head gasket problem is having the heads ported and polished and the intake done as well. the custom headers were just a bonus but they were expencive to make.

 

No real reason to mess with custom headers on an ls4 car, especially not a near stock one. There are $500 off the shelf headers, or used DT headers that'll bolt in. Only time I'd go custom on an ls4 is with a crazier build (larger cubic inches, or supercharged boost).

I also don't think porting and polishing the heads really applies either. The stock ls4 heads already flow plenty. It's a lot of cost to have it done correctly for virtually no gains at this point.

 

that's true though they do pretty much flow pretty good bumpin. I noticed a big difference on the 6 cylinder. gm has the flow right on the 8 cylenders than there 6 sad to say. because the newer 6 have more hp and torque stock than the stock older v8 engines. but not as much yet from gm