ddl6289

The timing chain broke on our 02Z during and HPDE. The motor is a stock LS6. If valves are bent (which is likely) we'll have to overhaul the heads. As a lower cost alternative I wonder if we can install assembled LS2 heads such as these:

http://www.superchevyperformance.com...p/12576063.htm

So here's my question: Are these heads a direct swap onto an ls6 or do other things need to be replaced such as push-rods or lifters?

Thanks,
Dan

AU N EGL

LS2 and LS6 heads are both 243 castings. The LS6 heads have the lighter wt valves then the LS2 Valves

Push rods on the LS6 are longer, do to the smaller diameter cam used in the LS6. Make sure these rods are not bent, even the slightest amount.

What I am not sure about is the diameter of the LS2 cam? is it the same diameter as the LS1 cam, and LS2 cam?? ppl who have swapped out Cams in their LS6 engines have gone to shorter robs.

Personally I would stick with the LS6 heads, if not even a PP LS6 head.

Good Luck

ddl6289

Hi AU N EGL:
If they're the same casting, why do you recommend the LS6 heads over the LS2? Is is simply the valves?

What is a PP LS6 head?

Also, our mechanic is recommending drilling/modifying the lifter guides for less oil retention? What are peoples' opinion of this?

AU N EGL

LS6 Heads have lighter valves and stronger springs then the valves and springs put into the LS2 heads.

PP means Ported and Polished, which provides more air flow into and exhaust flow out = more HP. and cleaning up the oil holes for better flow and less retention.

ddl6289

The GM Performance Parts LS2 heads come with 12586484 springs which are the LS6 springs.


With only an upgrade to ported/polished heads, what kind of HP increase should I see? 10 HP?

davidfarmer

The pushrods are not longer me thinks, I think the LS2 just uses the original LS6 cam which has the larger base circle. SO if you swithc to the sodium-valved heads, you need an 02-04 LS6 cam. OR you could use aftermarket pushrods OR adjustable rocker arms.

The head bolts changed sometime along the way too. That may be a block issue, not a head issue, but you might want to double check. I think the LS2 uses all the same length bolts, instead of the shorter ones on the top corners.

davidfarmer

just re-read the thread. I would get a set of the CNC-ported GM heads, stock combustion chamber size, and have at it. The LS2 heads are the same as your 02' heads except they have heavy valves. If your heads are undamaged, just put new valves in. btw, decent chance you didn't break anything.

JWIS makes a great drop in chain for the LSX. It uses the stock sprockets, so you don't need to pull the crank pulley off. You can get it from

http://www.thunderracing.com/catalog...d=349&pcid=222

This is what I run in my engines