Ok I've got an lq4 bottom end in good condition, I have new l92 heads and an ls3 intake. My problem is ptv/ compression / cam choice.. I really can not afford to buy new pistons and obviously want to make the best power I can . So my question is what kind of power losses can I expect from not milling the heads? And fly cutting, I know I can run tsp's 235/239 cam if I don't touch anything but will the heads support that much cam with that low of comp? If I have the pistons fly cut an mill the heads ill be spending close to what new pistons would cost... I don't know what to do here.. And sorry I asked this question before but didn't get to much input .

 

life is a bunch of compromises,I say run a different cam that will have safe PTV. if you run too big of cam and lower your dynamic ,you will effect potential power .how close are the valves to the cylinder wall ?if too close it can hurt port flow .

 

They will wind up close too I belive, any idea how much I should mill or what cam I should look at then? If I do mill the heads I won't be fly cutting unless we're talking about a substantial power difference ... But then I'm right back to almost spending what pistons cost.. But at that point It looks like I'd be better off upgrading to the ls2 style rods.. Lol this it why I don't want to touch the bottom end

 

http://m.summitracing.com/parts/wis-pt124as
What if I whent with something like this, anyone use these with l92 heads? Also it'd put me at 11.5 comp I belive ... Is that to much for pump has efi ? Also if like this car to be able to handle road trips from time to time

 

If I were you I would figure out what your compression ratio actually is with that combo and then figure out what your piston to valve clearance is and where you go from there also depends on what you plan on using it for. Daily driver, Street/strip, Mainly Drag.
Pick a cam that will work best for the RPM your going to see on a regular basis. Bigger isn't always better. If it's a daily driver you can always use a cam with less lift that will allow you to mill the heads to get compression up to a reasonable level and still use pump gas.
If it's street/strip use then you can always leave the heads alone and going with a cam that will work without fly cutting and spray it when needed. Gearing will also make a difference.
Like I said it all depends on what you intend to do with it. Throw enough cam/gear/stall/ nitrous in any motor and it will haul *** but won't be very happy on the street and may not last long.

 

I think I was way off with my math on the pistons I posted. But the car will be street and strip and possibly have to make a 300 mile trip from time to time , rear gear is 373. Trans will be a m6 . How far will I have to mill the heads to get the comp up with the stock pistons? And how much can you fly cut safely? Thanks for the info