Ask Away! with Jeff Smith: Getting to 400+ Horsepower in an LS1-Equipped Fourth-Gen Camaro

I have a 2000 fourth-gen Camaro with an LS1 and a six-speed that I just bought. The car runs great—but now that I’ve had it for awhile, I’d like to upgrade the engine a little. My budget doesn’t allow just buying a bigger crate engine like an LS3. It’s rated at 430 hp while my stock LS1 comes in at 305 since mine is not an SS. While that’s a huge jump in power, I’m thinking I might be able to get close to 400 hp just by improving a few things on my LS1. Would a top-end package of some kind (like heads and an intake) get me there?
B.C.

There are dozens of parts combinations available for the 5.7L LS1 engine. While that’s a good thing because it offers lots of options—it does make it difficult to come to a decision! We don’t have space here to show you all the different variations so we’ll offer a couple different ways to go and you can take it from there.

5.7L LS1 Performance Potential

The base LS1 engine has tons of potential. The stock cylinder heads flow very well compared to old school small block Chevy castings so you are already easily on your way to 400-plus horsepower. From a basic approach, it all comes down to airflow and cam timing, and then eliminating the restrictions to airflow either ahead or behind the engine. It doesn’t do much good to have really good flowing heads and a big cam if the air inlet is restricted or the exhaust is restricted with backpressure.

The point here is that purchasing just a cam, heads, and intake may not necessarily create the most powerful combination. It would also take fresh air induction, headers, and better exhaust to complete the system.

As an example, just adding a cat-back exhaust system could even uncork some hidden power in the stock engine package. For instance, Borla makes an S-Type Cat-Back Exhaust System with a stainless muffler and exhaust pipes that’s affordable, offers a million mile warranty, and will work very well with later engine mods.

5.7 LS1 Performance Camshafts

If you are considering this work in stages, one of the best power improvements besides a set of cylinder heads is to add a few degrees of cam timing, as it can do wondrous things to the mid-range and top-end power.

There are literally hundreds of cam combinations, so we’ll just mention a couple. If you are on a budget, Summit Racing offers a line of Pro LS Automotive Camshafts that work pretty well. The Stage 1 Ghost Cam is spec’d at 222/234 degrees of duration for intake and exhaust with 0.600/0.575-inch valve lift. This can either be purchased separately or in a kit with matching valve springs (which is an excellent idea). There are much larger, longer duration cams available but this is a good choice for a street engine that will be predominantly driven at lower engine speeds—which will make the driving experience much more enjoyable.

5.7L LS1 Performance Cylinder Heads

Now let’s move to cylinder heads. Here we have several alternatives. The easiest move for most of these situations is to purchase a new set of heads and, in that case for a cathedral port engine, you have tons of options. We’ll limit this discussion to a couple of heads, but there are probably a dozen from different companies and it might be worthwhile to investigate more.

Among the Dart Pro 1 LS offerings is a 225cc cathedral intake port head with a 62cc combustion chamber and 2.05/1.60-inch stainless valves. The advantage to this head, besides the improved airflow, is the 6cc smaller chamber that will bump up the static compression over a half a ratio—from 10:1 to closer to 10.6:1 (and perhaps more). This added compression will definitely improve power across the board but will also demand premium fuel.

Another option is the Trick Flow 220cc cathedral intake port head. It also uses larger 2.04/1.57-inch valves but runs with an in-between 64cc chamber. This won’t bump the compression quite as much unless you also went with a thinner head gasket, which is also a possibility.

A third option (and one that keeps the cost down) is to find a set of 5.3L 706 or 862 casting heads. These heads use smaller valves and smaller ports, but the advantage is in some judicious porting. But the main reason for these heads is they sport a 61cc chamber that, again depending upon gasket thickness and other variables, could push the compression ratio up to around 10.8 to 10.9:1.

We’ve done this conversion on a larger LQ4 6.0L truck engine that was very successful. Then, we had West Coast Racing Cylinder Heads (WCRCH) do a simple CNC porting program on these heads and install a larger 2.00-inch intake valve. We bolted these heads on a 4.8L LS truck engine with a 218 at 0.050 Comp camshaft and made 430 hp using a carbureted dual plane intake manifold. Now imagine running a much larger engine with a slightly longer duration camshaft. This could easily produce perhaps 440 hp or more.

5.7L LS1 Performance Intake Manifolds

Now let’s move on to intake manifolds. Your current LS1 intake is acceptable but will cost some power. As the old saying goes, “horsepower costs money – how fast you wanna go?” A good manifold upgrade would the factory LS6 or the LS2 version.

Altogether this engine has plenty of potential and has the potential to make well north of 430 to 440 hp.