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So once upon a time my LS1 started making noise. I put it off, assumed it was a leaky exhaust gasket.

Then I started having other issues now low and behold its a bad a lifter. Ate the cam a little and now I am looking to get a little more bump without the pistons making out with the valves.

I know my heads have been milled exactly how much and how to equate that to how much lift I can get is why I am here.

4.750 is stock height.

My head measure roughly in the middle of 11/16 and 3/4 at 4.

11/16 is .6875 so im roughly 4.71857 or roughly 30 over and decked?

Now I plan to have the heads cleaned and valves checked. Didnt plan on resurface as its already been cut a number of times. Also it didnt overheat I started hearing a tick and stopped driving it.

The heads a PRC stage 2.5 243 heads from like forever ago. I was at 360rwhp and thats with ls1 intake and ls6 cam. Id love to see north of 400rwhp with stock intake.

I looked at the LS7 STreet Cam, 227/243 .613/.623 @115.5 would this work? How do I equate my milled head to cam lift? What would be the max lift possible? Not that I need an MS3 cam or something similar but just for my knowledge if I go for a slightly larger cam.

The end goal is maybe throwing a 100-150 shot ontop that engine. Id like streetability for this whip. Id also like to make around 450rwhp N/A......but I dont have the money to throw a new intake on this car right now. So I know im looking at a slightly larger lift cam while staying probably above 112 lsa IE 114 and up. But I am open to suggestions.


Looking in from driver side lifter galley to passenger side lifter



....and of course the bad lifter is on the oppposite side that I get off first.

JakeFusion

iTrader: (7)

So, I don't know where that cam comes from, but that's pretty much exactly my cam. A 227/244 115+5. However, I have less aggressive lobe profiles - LSL/XE from Comp. Either way, the grind itself will work.

But, I think you need less exhaust, even with the nitrous. I did this cam for a Procharger I'm planning to do this year. And you can see around 2800-3200 it dip in power because of the added exhaust duration is overscavenging the exhaust. However, uptop, it behaves and performs pretty close to my previous cam, a 234/242 111+3. But it drives much better. And with my exhaust, still thumps like a sunofabitch.

The only real way to know if a cam will work is to measure it. You can do all the math you want, but stacking tolerances become an issue. I know that doesn't help you when purchasing, but it is what it is.

I think you are safe with a 227 intake lobe on a 110 or greater ICL. I'd recommend a 227/234 113+2 as a good cam that will make the power you want, drive nice, and still work with 150 shot easily. BTR has that cam and is a good option for you on the same LSL/XE lobe combo (which seems to make the most HP in his testing with stock rockers). I believe Tick has one very similar as well.

Edit: Here's a dyno showing the BTR Stage 2 with stock 243s. Your heads are 30HP better than those... I don't know if you have the other supporting mods, but this shows you can make close to 450 with stock 243s. I would venture if the guy posting this went to TSP, TEA, or AI heads, he'd be pushing 470-480rwhp.

https://ls1tech.com/forums/dynamomet...243-heads.html

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I really appreciate your input. I think Im going to just call up Tick on monday and see what they might say.

01ssreda4

iTrader: (96)

http://store.cammotion.com/the-titan4

JakeFusion

iTrader: (7)

Titan 4 is pretty much that same profile as well. Although, I do prefer more exhaust duration with stock heads. An 8 or 12 degree split works very well.

CAMMOTION PERF

Since the heads have been milled multiple times, and the heads being modified with aftermarket valves, the only real way to know how much camshaft that you can fit is to do what is called a "valve-drop measurement".

Here is an excerpt on that from something I wrote a while back:

Valve Drop
The object of measuring valve drop is to determine how far a valve can open before it touches the piston while that piston is at top dead center in the cylinder. Knowing this figure is the only way one can estimate piston-to-valve clearance without actually measuring an assembled engine. Furthermore, knowing this allows engine builders to determine which camshafts might fit in a given engine without further modification. There are two ways to measure valve drop. Actual valve drop (assembled) and estimated valve drop (not assembled).
Actual (assembled) Valve Drop
The most fool proof way is to measure valve drop in an assembled engine. Just rotate the crank until the the piston is at top dead center and then, with the valve spring removed or with a checker spring, lower the valve off of the valve seat until it touches the piston. Whatever that distance is, that is your valve drop. Do this for both intake and exhaust valves as they are most often different. This is done with a dial indicator resting on top of the valve tip to measure the distance accurately.

Estimated (unassembled) Valve Drop
You can also estimate valve drop while the cylinder head is not on the engine. For this start by placing the cylinder head on a flat surface. With the valve springs removed or with a "checker" spring, lower the valve until it touches the surface on which the head rests. Use a dial indicator resting on the valve tip to measure this accurately. This measurement of how far the valve "drops" is your cylinder head valve drop. Next measure your piston to deck height relationship. Most stock LS engines have a positive deck(between .005" to .008" is most often reported by builders). Next measure the thickness of your head gasket. The formula looks something like this: Cylinder head valve drop + head gasket thickness - positive deck height = valve drop. this is very accurate for an engine equipped with flat top pistons. Here is an example:
.155" + .051" - .007" = .199"
Again, do this for both intake and exhaust valves as they are most often different. Also, engines with dome pistons or dished pistons might better be done assembled as it is difficult to account for the different piston surface shapes using this method.

If you can accurately perform this measurement, I can tell you what camshaft specs will fit.

~Steven

Martin Smallwood

iTrader: (2)

This x2.