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iTrader: (1)

I'm having my stock heads hand ported and valves opened up...I've got a few questions.

1. How much can you shave the heads and use stock length pushrods?

2. How much can shave the heads and still get the intake (LS6) to line up with the intake ports?

2b. Are their any special intake gaskets to aid with question 2?

3. How much can you machine the stock valve seats before you need to replace them with larger ones?

4. How much would you need to mill the stock heads to bump the CR to 11:1?

4b. What's the thickness difference between the GM head gaskets and the thinner Felpro's?

The car is an 02 SS running SLP Long Tubes, ORPs, SLP 345hp intake with an M6.
TIA

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iTrader: (1)

Okayyyy, I've found (using the search) that it will take about .035" to bump the stock heads to 11:1 Of course this will depend on any chamber work done such as unshrouding the valves etc. They will need to be CC'd for exact calculations.

I still need to know about intake mainfold/head matching? Any tips out there to get me going the right direction?

Looks like the heads will be about .035" shorter than stock. Will I have problems with the intake manifold?

Will stock length pushrods work with the heads shaved .035"?

...and also the valve seats, anybody know how much (if at all) they can be opened up prior to being replaced entirely?

PREDATOR-Z

No problems with intake fitting.
7.40 p-rods with thin gasket
Stock cam??

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iTrader: (1)

Thanks Predator Z

More details...

The cam will be a Comp Cams stick...I'm looking at 228/230 .580ish lift to maybe 231/237 .589/.592 both with 112 LSA.

The heads will be loaded up with new springs (duals or ???) Ti retainers, new seals and locks and likely 2.05" intakes.

The car is currently making 340rwhp with stock internals, headers, ORPs and DSP tune. I'm hoping to find another 100 (usable) horsepower.

I have no smog inspections to worry about and the car is not my daily driver.

I don't have an adjustable pushrod to get an accurate measurement so I was wondering if there is good information or a table that could tell me what length pushrod for a given change in valvetrain height. I.E. milling the heads and changing the gasket.

Oh, it also looks like the aftermarket gaskets can offer a .010" reduction in thickness. That would reduce the milling on the head to about .025" Are the thinner gaskets more prone to failures?

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iTrader: (1)

Looks like I'll need to find or buy an adjustable pushrod to do the job right.

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iTrader: (1)

I'm also looking fo ra set of LSx heads.
I'm looking for inexpensive set of used heads I can have custom ported and revalved with maybe 2.05" intakes. This way I can send the new(used) heads to my machinest for porting and new valves and not have to look at my car with it's parts all over the garage for 3-4 weeks.

As I stated above, I'm shooting for 11:1CR
Given that the heads will be hand ported and flowed, which heads would be best on an LS1;

the 5.3's with a thin gaskets looks like they will require very little maching to reach that target. Therfore the pushrod length and valve geometry should be very close to stock.

5.7 will be a direct replacment, but so what, all the OEM parts will go in a box to be stored under the toolbox for decades

LS6 more costly, how much better is the design considering either set will get reworked and massaged to get the best possible flow.