LS3 Cam and valvetrain upgrade

[Maloo 176]

Now im a bit closer to what i maybe do.

Cam
.629/.615 - 229/244 112 lsa

Johnson Lifters Link bar (fit without plastik lifter trays cause the link bar?)

Yellaterra roller Rocker shaft mount

Valves ferrea 6000 or better

Mill the heads 0,5mm and thin gaskets

0.7mm flycut for intake and exaust valve

Pushrods in length for 1 mm preload on the Lifters.

Its manual transmission 16kg flywheel incl. clutch

Once a year a drag race day...
Maybe 5000km a year.
3000 + km vacation trips (like visit alice springs start at sydney once a year)

 

[07GTS]

stock LS3 valves are fine there will only be a cost to swapping those and no performance gains that u would notice, yep johnson link bar lifters dont use the buckets, they require 0.035'' preload give or take 0.010'' each way, this is critical to be within for proper lifter operation as the johnsons are a shorter travel, measure all of them once heads are fitted to see what length pushrods u need

 

[shane_3800]

Now im a bit closer to what i maybe do.

Cam
.629/.615 - 229/244 112 lsa

Johnson Lifters Link bar (fit without plastik lifter trays cause the link bar?)

Yellaterra roller Rocker shaft mount

Valves ferrea 6000 or better

Mill the heads 0,5mm and thin gaskets

0.7mm flycut for intake and exaust valve

Pushrods in length for 1 mm preload on the Lifters.

Its manual transmission 16kg flywheel incl. clutch

Once a year a drag race day...
Maybe 5000km a year.
3000 + km vacation trips (like visit alice springs start at sydney once a year)

The cam seems a little too large on the exhaust, I would go fdor one with a little less exhaust duration maybe 240 or 242 and maybe a 111 or a 110 LSA.
Just my thoughts, I could be wrong.

 

[Maloo 176]

Thanks for the preload Info 0.035in 0.9mm...

Which cam has 240/242 or something Like that.

The one i thought was Texas speed stage2
Or btr Red Hot .619/.617- 221/24x 113lsa

I think all this isnt that different to my ls7 Cam If i would go for 1.8 Rockers.
Ls7 .593/.589-211/230. But 121 LSA

I have a pair of l99 heads they don't have Natrium filled valves and i need at least 4 valves cause the l99 had Piston contact on Zyl 7&8

Or i put my ls3 valves in the portet l99 heads.

 

[shane_3800]

The BTR red hot is just marketing BS, it states 24X on the exhaust, What they mean by that is it lofts heaps.
Loft only really helps if you have 8000rpm plus.

But in saying that the red hot cam does make some good power, it all depends on the intake too.
What intake are you going to run? if stock LS3 (good choice) just use the BTR cam and get the heads done with good valves.
If you can find a shop in the EU that has a Serdi Profile machine go there as you will get a better valve job.

 

[shane_3800]

This will explain a little about cams, you should probably email this guy, he could sort you out with what you want in cams and grind one for you.

 

[shane_3800]

Also one of the reasons why I said to knock some exhaust duration off, is that is really a thing for stock SBC heads to extend the exhaust duration out to compensate for poor port performance, lots of people think it's the lift but the lift is actually an artifact of the duration curve.
But the have a 14 degree split is not needed on a LS3 head, yes the head it self will have a big exhaust to intake ratio but the MCSA on the intake is so large it's not fully utilised, so the massive split is not needed.
hell you really only need a 4-5 degree split in my opinion, then use the LSA to adjust, so if you need more low end bring the LSA in tighter, but that will make it idle like a dog. Widen the LSA and it will smooth up the whole curve but drop off on the bottom and start climbing which is a shitty curve.

 

[07GTS]

the LS has always had an imbalanced valve system where the intake is fine and sometimes too much but the exhaust is restricted, u just need enough exhaust to get it all out so the intake is as fresh as it can be without left over exhaust, but going too far starts to make it an early opening exhaust valve which helps with top end but will start to hurt bottom end, on the inverse because the intake valve is so big if u hold the intake valve open too long it then with push ur cylinder fill back out the intake valve,

the ls7 cam is not good for n/a unless u have 427 cubes to help it, the wide LSA puts the torque band wider and more up top and if u dont have the cubes u will loose alot of bottom end, the LS9 cam has no bottom end when used n/a but does peak above 4k well but that dosnt help street as that needs the PD blower down low to help it out, a cam in the 220's is good for intake and mid to late 230's exhaust is good all round on a LS and LSA in the 112-116 depending where u want the torque curve and .600-.620 lift intake, the exhaust dosnt need any more the .600 lift because of the smaller valve

 

[shane_3800]

Honestly the money would be best spent on a stroker kit, and a mild cam upgrade, you will do better to draw on an LS3 head with stroke rather than stock stroke and RPM.

 

[shane_3800]

the LS has always had an imbalanced valve system where the intake is fine and sometimes too much but the exhaust is restricted, u just need enough exhaust to get it all out so the intake is as fresh as it can be without left over exhaust, but going too far starts to make it an early opening exhaust valve which helps with top end but will start to hurt bottom end, on the inverse because the intake valve is so big if u hold the intake valve open too long it then with push ur cylinder fill back out the intake valve,

the ls7 cam is not good for n/a unless u have 427 cubes to help it, the wide LSA puts the torque band wider and more up top and if u dont have the cubes u will loose alot of bottom end, the LS9 cam has no bottom end when used n/a but does peak above 4k well but that dosnt help street as that needs the PD blower down low to help it out, a cam in the 220's is good for intake and mid to late 230's exhaust is good all round on a LS and LSA in the 112-116 depending where u want the torque curve and .600-.620 lift intake, the exhaust dosnt need any more the .600 lift because of the smaller valve

I agree, but if the exhaust is stable on the bench close to or at square so 1.600" then it will take as much lift as you can throw at it.
Most measure to 1.000" or 1.100" to see how stable the port is.
But you have to remember that the exhaust starts off at supersonic and is like a blow down event for 1/4 of crank rev.