I don't think the installed height is as much of a factor as the seat pressure....and you better believe it's gonna be up there on a cam like that. Also, if you are talking about a stock internal LQ4, the cam mentioned is gonna be pulling and making power at RPM's that will eat that motor alive. The operating range for that cam cannot match up with a stock internal LQ4, I mean, how far do you plan on reving this motor anyway?? Then comes the issue of the Truck Intake manifold and high RPM, and then.....

IMO, this cam sux for trux...especially a D/D stock internal, truck intaked LQ4. You can argue it anyway you want. You prob. didn't notice that the guy that posted that thread also has 225AFR heads and a PORTED Fast 90/NW90 also. It's a little more to it than just putting it in a 4500lb vehicle with a stock LQ4 and hopin' to get lucky.

I'd PASS

 

 

I set a guy up with a high lift cam in his stock headed, LQ4. It's a 230/226 .612''/.590'' 109LSA. Running it on the regular old 918s and stock valvetrain. Runs mid 12s on the stock gearing/g80 crap and still spinning.

I'm using a 214/212 .600''/.571'' 108LSA with the same valvetrain as above in my 5.3L. No track times yet because everything loves to break.

 

How do you figure? If oyu got two cams with the same duration and one has higher lift the one with higher lift is going to have more of a chance of hitting the piston. DUration effects to P to V much more then lift to an extent but lift should still be taken into account not to mention the heads are milled.

On the future head comment, you realize what kind of heads its going to take to see any noticeable difference? BIG heads, bigger then what oyu need on a stock LQ4.

On the spring wear deal. Its quite simple, the further the spring is compressed the more range of motion it has to go through, the more it has to move the faster it is worn out. The harder you play a sport the faster you get tire right? Same concept. Not to mention the springs he will ahve to run cost twice as much for that high a lift. With the 581 he can run 918s, with the other he will have to step up to duals.

 

Ok folks I thank ya and from what i have read just from here and been reading up on last night, I am going to stick with the 581 deal. I am planning on upgrading to a set of ls6 heads down the road, probably a ls6 intake. I am only going to do rod bolts to the engine, untill it takes a ****, an if it does..And just from thinking then seein it posted, there will be alot of seat and spring pressure on the v train.I also don't want to spin a stock 6 to where I will have to in order to make the power with this cam, being a DD.. i guess I am just gonna have to stay more pratical. I think that my orignal choice will get me where I want for now and if it does not I will just have to get some vitiam C (juice). So again thanks to everyone who posted on this thread..

Thanks JOHN

 

Anyone care to speculate where the hp peak will be with the bigger cam?

Saying it will be too high for a stock 6.0 doesn't make sense to me.

It's only a 223 on a 112.

Can't you run a 6.0 up to 6500 daily?

More lift = higher rpm peak hp?

I don't see it?

I can see the spring issue, but I think it would be a good choice otherwise.

 

Moddoo, you are right. You have more lobe area for a given .050'' size. For example, it would take nearly a 234*-.576'' X-E lobe to compete with a 223*-.636'' LSK lobe. Now, put them on the same LSA and you have the LSK lobe with roughly 10* less overlap!

 

Bad idea. Fat stall!!!!!!!!!! Get a cam that will work well with the heads you have now. Not the heads your planning to get in 5 years...........

Besides, if thats a single pattern cam. .636 on the exhaust side is worthless. What are the valve events on that cam anyway?

 

[QUOTE=1slow01Z71]How do you figure? If oyu got two cams with the same duration and one has higher lift the one with higher lift is going to have more of a chance of hitting the piston. DUration effects to P to V much more then lift to an extent but lift should still be taken into account not to mention the heads are milled.[QUOTE]

Your right I meant to say duration effects it more than lift. But I definitely would not put that cam in with milled heads with out checking PTV clearance.
You don't want to be one of the guys on the net blowing up a motor.