OutKlast

iTrader: (2)

Background specs:

Car: 2000 Corvette FRC (Fixed Roof Coupe)
Engine: LQ9 Iron Block 408ci
Misc. engine specs as-is:
4 callies crank
eagle rods
diamond pistons
ATI damper pulley
Absolute speed heads W/ 2.08 1.60? valves flow 325+
custom ground cam its a 244 248, 61x 61x 114
Comp r lifters
Hardened push rods (7.350" Trick Flow)
C.R 11.6
90mm fast intake and TPIS 90MM TB.
38# injectors
Granettelli maf

(dynoed 519.9 rwhp / 486 ft-lbs)

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Background info:

I was planning on swapping the valve springs in the car as I had some loud top end ticking type noise that had gotten pretty loud recently and its around the 30k miles mark for them. So I started to tear down the engine when I see the top of one of valve stems is smashed and the rocker for that valve is also damaged. Now I have to take off the heads and thus all the crap in the front/drain the coolant...yadda yadda.


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Currently on my install list:

Patriot Stage III heads with valves/dual springs good for .650" of lift. (https://www.patriot-performance.com/...&cat=35&page=1)
LS6 PCV setup
New roller rockers (brand/type unknown, suggestions welcome)
Ported oil pump (unless mine is already ported)

Possibly new push rods, length/type unknown, possibly a new cam.


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CAM talk:

I'm thinking about swapping the cam for something more street friendly/warm weather friendly. The car runs very good in moderate to cool S. Fla weather. But in the dead of summer it struggles to idle with the AC on, with the AC off it is fine. But the car is black and its FL so its like 130*+ in the car with the AC off. Basically when its really hot and the engine is warm and the AC is on the rpms will start bouncing around when sitting and idling (meaning it will drop 100 rpms off idle then rev to 100 over and continue until its dropping to 500 rpms and revving to 1500rps on its own). Also another issue is if you start to give it a little gas and slip the clutch just to move a little or to make a U-turn etc the engine sometimes stalls when you suddenly push the clutch in and take the load off the engine. Driving it is fine and runs the AC no problem. A hole in the throttle body would probably somewhat eliminate the issue as you can keep it from rev jumping by applying just a hair of pressure on the gas pedal but I really don't want to do that. Also its been tuned by more then 1 tuner same issue stays.

I'm also kind of looking for a different sound, the sound right now has been described by the police and others as sounding like "an outboard motor out of water" or like a "powerboat".

Current cam idle: http://www.youtube.com/watch?v=P836CE-ag5M
Current cam low rev: http://www.youtube.com/watch?v=Dh3hoMvxM8g

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Looking for suggestions on what to add, specific parts for what I already plan on changing out, general suggestions etc. Lemme hear it.

OutKlast

iTrader: (2)

I'm thinking maybe I should replace the lifters while the heads are off.

Nitroused383

iTrader: (10)

I'm not really sure why you want to replace your heads with something that probably flows less than what you have. Also I'm not sure what combustion chamber size your current heads are but the ones you listed have 72cc's and thats probably going to lower your compression. If people tell them your car sounds like a power boat, just tell them thats the sound of one bad mother f#cker. Are you trying to detune the car to make less power or do you want to make more power while doing this? I think the ac issue you have can be tuned you need to ask some other tuners.

If your goal is to really upgrade what you have than I suggest you get your current heads fixed up and sell them. Than buy a set of Trick Flow 235 cc heads and you will make some great power. Unless you go with a real small cam your car is always going to sound like a cammed LSx motor. I'm not really sure what you are trying to accomplish so we need a little more information. If your only real complaint is the ac issue than that is a pretty simple fix. You might need a set of new pushrods if any of those are bent.

01ssreda4

iTrader: (96)

could you raise the idle to help it idling with the AC on?

99 Black Bird T/A

iTrader: (4)

I'd keep the Absolutes before putting Patriots on the car. If you want to change heads, fix and sell the Absolutes and get some Trick Flow's like mentioned above.

With the Trick Flow's you could probably go to a smaller cam improve the idle and make excellent power.

What about upgrading from stock rockers?

OutKlast

iTrader: (2)

First off thanks for the replies.


I'm not too terribly concerned with loosing some power. However I think I'm not going to update the cam as what I have seems pretty standard for a big block and although I'm not real worried about power I don't want to 'cut off my legs' so to speak and drop the power level down to the low 400's either. Also you have to drop the steering rack to change it, screw that.


On the issue of heads the reason I was considering the patriot heads was not as an upgrade but just to simplify things as the heads would be clean and new with valves/valvesprings already installed. I figured they would lower my compression ratio a bit but that didn't concern me too much. Also just running the numbers as long as I could sell the heads I have now for ~600-650'ish it would be a breakeven thing. How hard is it to install valves anyway? any special tools needed?


Also the trickflows look very nice for sure but the price to performance on them is not quite there. As they're about $~1,200 more for what *might* net me 15-40 more hp. I could pick up a baby shot of nitrous and a small kit to bridge that gap easy and with a forged motor and the valvetrain updates the engine should be lol'ing at 150 shots and under.

OutKlast

iTrader: (2)

I decided to keep the heads I have and to not update the cam or oil pump.

My shopping list, please check for missing stuff (click for link):

Main parts:
LS7 Lifters
Yella Terra Roller Rockers for LS2, L76, L92 & L98
Are there other strong but cheaper valves in the 2.08/1.60 size?
Manley Race series intake valves 2.08
Manley race series exhaust valves 1.60
LS6 PCV conversion kit
160* Thermostat


Already purchased
Dual Spring Kit w/ locks, retainers and intake/exhaust valve seals

Gaskets/Seals
LS2 Head gasket, x2
FAST Intake seals
GM water gasket

Misc unlinked:
7 quarts oil + filter
Coolant

If its not listed I didn't consider it so I'm missing a gasket or similar please list it. Do I need to replace my head bolts? Also another site recommended replacing the lifter trays, should I? Do I have all the seals I need for the valves?

Thanks.

NC98Z

iTrader: (1)

A pair of high clearance DMH cutouts would give you an adjustable sound. It does have a kinda boat motor sound to it. I would have thought that with the cam your running now you would be a ground shaker.