Im looking into doing some work on a set of heads on an 01 WS6 ls1. Here is some background. Holley intake, headers, current cam is small mostlikely going up to a Trex or MS, obviously supporting mods. stock bottom end for now and no spray or other adders. I have to alot of work on a set of head at school (valve job, new valve seats, etc.) I was wondering what the best heads to get and port, install larger valves, etc would be? Stockers, 5.3, etc?

 

LS6 all the way!

 

First I would be stoned to death if I didn't mention that you need to get rid of that Holley intake because I am sure it is a metal intake and go to the LS6 manifold.

Second the best head for growth and making good power is the 243/799 (Same head different casting number). While the 5.3 heads are great they come to a point where you are either going to have to go with the 243s/799 or after market. Now the right set up will yield great performance with any head but if you are looking to add more later down the line the 243s/799 is your best budget minded head that you can pretty much go to 600+ hp with no issues.

You can pick up a set between 400 to 500 dollars.
LS6 valves are great addition to having strong and light valve train.(specially with bigger cams)
Stay with the stock rockers if you get a set and do a trunnion upgrade they are the lightest most reliable rockers out there.

Good luck.

 

One thing with the stock bottom end is make sure you have enough piston to valve clearance when switching to a camshaft as large as you want to go with. If you are willing to flycut the pistons then that is fine, but I will say that bigger valves/milled heads are not going to work with those camshafts.

 

ok, whats the largest cam i can stick in it without messing with the bottom end. also is a 2.02/1.60 set up the best? or what?

 

It all depends on what lift you get with the type of heads you want to be using.

 

No it depends on duration, LSA and advance............ You can pretty much ignore lift........

HG thickness, mill, valve size, also need to be considered. After market heads will usually clear more too.....

 

Ignore lift??? uh what.. Did you misread his repsonse? Of course lift is important when putting together a head and cam package.

 

you cannot ignore lift... yes all of those need to be taken into account as well I was just making a point that you need more numbers to get a clear answer. You can go ahead and keep ignoring lift... but im gonna go ahead and use it and for his sake I hope he does to.. When talking about not having to touch the bottom end.. cough flycut cough... would take into account lift. A higher lift means pushing the valve open more (closer to the piston). So when answering the question of what is the biggest CAM i can get without touching the bottom end it depends on what heads you choose. I think the LS6 head valves are longer than the 5.3 a little. or somethin like that.

 

so with a cam that large i have to fly cut the pistons?

 

It really varries... if you have a Cam with a long duration but not a big lift you might not have to. When you get into like an MS4 with LS6 heads then I think you have to. Always check the PTV clearance when you install the goods. Say you want to run the 5.3l heads and decide on the MS3 Cam.. you can always search on here and im sure its mensioned somewhere if they needed to flycut. but the more of a lift you have the more chance you have of needing to flycut.

 

You can have 700 lift on the cam and as long as the duration is correct he will NO PTV issues. Lift has very little if anyting to do with PTV in these engines. The LSX engines have a great clearance for lift. The issue comes in when the valve stays open a little more than it should (Duration) and then the piston and valves try to shake hands make friends and not so much. Why do you think that people run the MS4 cam and with the correct set up they no PTV issues. Its duration, LSA and advance like stated before.

 

Lift plays a small part in piston-to-valve clearance, but maximum lift occurs when the piston is further down in the cylinder on a 4-stroke engine. It's just the way the cycle works to make power. A very large duration cam holds the valve open longer, so that when the piston starts to come back up the cylinder bore for the compression stroke, the piston can tag the valve if there isn't proper clearance.

Anyway, the best head will depend on your budget. Ported 5.3 and LS6 heads from PRC, TEA, and Ai are very good values and offer good performance. Depending on what stage you choose, you will get either 2.00 or 2.02 or 2.05 valves intake or 1.55/1.57 or 1.60 exhaust. Larger valves of course reduce piston-to-valve clearance. So does milling the head for added compression. A 5.3 offers smaller combustion chambers for more compression, but doesn't flow quite as well as an LS6-based head.

If you step up to an aftermarket casting, you get better spark placement, thicker decks, more piston-to-valve clearance and higher performance. AFR, TFS, and PRC are common and are in the $2100-2300 area and generally need ~$400 roller rockers for best longevity/performance. TFS also has as-cast heads that are in the 1700 range that offers the benefits of the aftermarket castings without as much port work. But they provide good power as well and a good base for a ported like TEA or Ai to work with later if so desired. PRC offers the best piston-to-valve clearance and AFR has the smallest port for the best throttle response.

With any of the options, you are looking at a 35+rwhp gain over your stock heads upto 50rwhp+ with milled and aftermarket castings.

 

Honestly, i want to get a set of stock castings, port the **** out of them, install larger valves and seats (have the equipment at school), and not have to worry about the bottom end yet.
So with this said, whats the best casting to put even 2.0 and 1.5 valves into? i am not going to do the porting myself most likely

 

SDPC #243 $900 for the pair.can get 853s and 241 for $200.I do not think you can do a set of heads better and cheaper than the PRC stage 1 LS6 ,$1000.get a free set of heads to practice porting on,don't screw up on some 243s.

 

I guess I didn't even think about that.. im still sayin lift can't be ignored... long duration with low lift might be safe... long duration and high lift.. might not be safe.. or is that wrong also? is lift just a complete pointless number to put on there?! it this obama's fault?!

 

Does anyone know how large of a valve i can use with a cam this large? or is there a better cam to use?

 

the smaller valves give you more clearance.a head like TFS with a 13.5 valve angle helps also.get a costume cam ,not much more in cost,dose every thing you need it to do.contact PAT-G ,you won't regret it.

 

again, i want to use either a 243, or other stock casting. this thread is because i want to make the set of heads the way i want it. honestly all i would have to pay is porting and parts (valves etc)

 

any opinion on a set of 853s?