steel_3d

I'm pulling my engine for a partial rebuild at 115k due to some bad rings and bearings. While I'm in there I figured I might do some small power mods. But I don't want to mess up the good stock manners of the car. Don't want a lopey idle. It's completely stock, and I probably won't even go as far as changing the exhaust or headers, except maybe to a z06 setup. I autocross.

So what cam is worth getting, if any?

If I'm getting the heads refreshed, what's worth putting in there for cheap? Springs? Rockers? Are new springs mandatory with the recommended cam?

Is it worth milling the head? Or am I just asking for trouble with geometry changes? Don't want to worry about piston to valve clearance issues, weird wear, etc.

I assume any one of these changes will require a tune?

What would you do? Again, I'm a very mild guy, I'm happy with the car as is, but if it's apart anyway, I won't look a gift horse in the mouth... It's gotta be cheap, effective, smooth, and pass emissions, or I'll skip it.

Thanks!

SpinMonster

500rwhp has been done quite a few times without touching heads.

Has anyone actually exceeded 500rwhp with ported LS3 heads on a stock bottom end? Im not interested in hearing about engine dyno combos tuned with race gas.

steel_3d

Remember, I'm not wanting to make other mods than what I stated. I also don't want to port my heads. Just a valve job, decking, cam, simple stuff.

old motorhead

I'd do a clean up mill on the heads along with valve job, new seals and springs appropriate for the cam choice. If you're looking for an off the shelf grind, TX Speed has an interesting one that would fit your criteria. It's a 225/230 .610 or so lift. It's available in wider LSA's. A 115 or 116 would make for a nice daily driver with extra go at just about any rpm.

Alvin@PCMofNC

We've got a really mild cam that we use in LS3 cars for guys who want the sound and performance but do not want to give up an ounce of drivealbity. Here is a graph from one we did. Stock, just the cam, then just the cam + porting the stock heads. It was a really budget friendly build. The cam is awfully small but still sounds good. I would bet that it would pass emissions with a good tune. If a sniffer test is absolutely required you could cut something even smaller and maybe only loose say 10-12 rwhp from this setup.

Why do you want to stay with stock manifolds? Just curious? We know of several autocross and road race cars with headers.. In fact we just installed a set last week.

hungryhippo

You should definitely mill the heads if there's enough clearance. I had a cam and ported heads done first and wasn't that happy with the performance (even at 501rwhp). I then went back later to get the heads milled and pistons flycut. The increased compression really transformed the power band and throttle response. You should also get the Z06 manifolds since they are so inexpensive and look stock still.

Alvin@PCMofNC

Just be very careful decking the heads on a LS3 car. They do not have much P2V clearance to start with. I've personally had mid 220ish duration cams come close on a set of heads that where only decked .030''

http://pcmofnc.com/index.php?option=...ches&Itemid=56

steel_3d

Any opinions on this TSP 225/230 kit?
https://www.texas-speed.com/Shopping...roductID%3d249

Anything cheaper out there?

Alvin, which one of your cams do you recommend if, like I said, I want to pass the sniffer test? Do you have it in stock?

Thanks

steel_3d

What about staying with stock cam and just milling the head .030? Any drivability/torque/power gains?
Will the piston to valve clearance be ok? Do I need to worry about valvetrain geometry?

slapahondn

I've heard the zr1 cam will give you a few extra hp and will run and idle like stock.

AVB

Since you don't want lope, ask the tuner you plan on using and ask to drive one of his recommendations. I had an LS7 in my LS3 and was happy with the stock manners but went with a smog-able PATG cam cause I needed a little more.

Because it sounds like you want a mild cam, the LS7 manifolds plus what is a good match for the cam, for intake improvements.

Oh and dual springs for good measure...

old motorhead

LS7 cam in an LS3? I always thought that was a better way to go than the LS9 cam that lots of folks are so enamored with. Same exact lobes, just a narrower LSA (which is good). It will work with the stock LS3 springs too. That might be a good way to go for the OP.

How big did you go with the Pat G cam and still pass emissions?

AVB

I liked the LS7 cam a lot... in fact I still have it just in case I need to go back. The cam is a 226/235 on a 114 and did require a specific "emission friendly" tune

For the OP, since I probably wont ever need to go back to the LS7 cam, it's available if interested.

steel_3d

Doesn't the ls7 cam require longer pushrods due to the smaller base circle? Is it a 3-bolt as well? Only ls3 is 1-bolt?

Vette Threat

That's a popular cam for the street. I believe someone on this forum made about 490RWHP with that cam and a set pf PRC heads. You could definitely tell there was a cam in the idle but still sounded very tame and drove close to stock.

0Anthony @ LGMotorsports

Since you haven't said it, and I don't know of anyone that has asked but these are the questions I would be asking first on a daily driver.

1. Manual or automatic?
2. If auto, what size stall if any would you want to do?
3. Desired RPM power range?
4. current RPM range you drive in
5. mileage? or is that a consideration
6. Other modifications to support larger cam/head

I would say the RPM range is something that you should look at more than anything. Not only that but drivablity is different to everyone. Once you get those planned out it is generally a bit easier to choose from.

Of course if you are going to put a stock LS7 or LS9 cam in the car, you know it will not drive that much different than stock.

Given the rules you have to pass out there, picking up a full LS7 exhaust setup would be a good idea. That is a good 15 hp right there and it still passes visual inspection as well as sniffer depending on what you do with the cam.

old motorhead

I believe the longer p'rods are due to the LS7's higher ratio rocker arms. The installed height on the valve springs of the LS7 is higher. You'll notice that the lift on the LS7 cam is higher than the LS9 cam. The lobes are the same....the difference is the LS7's 1.8 ratio rocker arms. If you divide the LS7's lift by 1.8 and multiply the result by 1.7, you'll get the same lift as the LS9 cam.

I think you're right about the 3 vs 1 bolt cam. You'd have to swap the cam sprocket to an LS7 unit. Cam sprockets are pretty inexpensive.

old motorhead

I'd bet it was on a 112lsa too. That's the way they usually sell the cam. If you use the same specs, and have it ground on a 115 lsa, you get 6 degrees less overlap. Better manners and a smoother idle would result. Peak power would move up in the rpm range a little with the wider lsa too.

AVB

It is a 3-bolt and while using it was using the stock LS3 pushrods w/ which showed the right lash and still quiet valvetrain.

Vette Threat

Another reason most go with the LS9 cam over the LS7 cam in an LS3.

LS9 cam plus LS7 manifolds and a tune is good for 45RWHP. Better than headers and cheaper too while keeping it all factory GM and stock appearing.

LS9 cam ...................$100
ECS tune+throttle .....$150
LS7 exhaust.............. $300 avg

45RWHP and a snappy linear type of throttle response for $550 and all factory parts? Giddy up!!