Fastcount03

iTrader: (13)

I have recently purchased a set of 243 heads and a 04 Z06 cam to install on my 03 5.3. I have had the heads ported and polished, milled only .005 for better seal, and upgraded to a set of Lunati springs. Now the questions I have are... Will everything else work with this combo and what are some things I should do while in the midst of the install to further unlock HP? Any suggestions are welcome. I am fairly new, so any input would help before I get in too deep. lol

InchUp

iTrader: (2)

Well before you go any further know ahead of time that with those 243 heads, even milled down .005", you're still going to lose compression. The stock 5.3L chambers are 61.15cc, and the 243 heads are 64.45cc. Knocking them down .005" is only taking off a couple, so instead of sitting at 9.4 or 9.5:1 compression you're now losing compression more towards 9.2 or 9.3...calculate the actual figures with some online calculator, right now I'm bored in math class typing on my cell phone. Bottom line, you're losing compression so either look into flat top pistons or ask your machine shop how far the 243's can actually be milled down to in an attempt to bump up your compression.

As for the Z06 cam, good choice. No complaints there for a cheap and proven camshaft (just know that camshaft was designed to bleed off compression in the LS6 to run 87 octane on a stock tune...).

sickREDsierra

iTrader: (17)

damn. you have been typing all this **** on your cell phone?

must be a slow math class for you. i couldnt type that much on a cell if i had all day.

Fastcount03

iTrader: (13)

LOL Yeah that is kinda what i was thinking!

As for the compression issue, I had planned on goin with a shorter gasket. My shop guy told me that would keep me damn near at the same ratio. I'm not very knowledgeable on this issue, so I am not real sure.

InchUp

iTrader: (2)

Use the search feature and search for "quench" and read up on a few bits of information by the member hirdlej. Second, take what you hear from your "shop guy" with a grain of salt. If he actually said to increase compression by going to a thinner gasket, then I'd say he knows very little about the inner workings of a motor.

AdioSS

iTrader: (2)

what do you mean by that? It is a common way to increase compression that works.

Fastcount03

iTrader: (13)

Yeah I do believe that by lessening the gap between your block and the combustion chamber decreases volume inside, therefore increasing compression ratio. That is the purpose of milling your heads down, to decrease volume inside your combustion chamber, in turn increasing you compression ratio. The LSX gaskets are a bit thinner than a stock truck gasket. So they would do the same thing, just alot less money.

InchUp

iTrader: (2)

Did you even search before asking this question? Again, search threads posted by hirdlej on the topic of "quench".

One should be more concerned with quench distance between the piston and chamber along with how much the piston is in/out of the whole at TDC. If anything, get your quench distance spot on and forget about compression ratio when it comes to the thickness of the head gasket. If, after your quench is spot on, you still need more compression, mill the heads more or change to a flat top or dome piston. The head milling being the cheaper route.

Fastcount03

iTrader: (13)

I appologize about the lengthy time it has taken me to reply. I did some research on quench and I understand what it is and how to measure it. Where could I find any of the measurements for a stock rotating assembly, or would I just have to wait until my heads are off and measure then, and then decide what gasket to go with. Cuz I had planned on just doin it all at once. Taking heads off and putting them back on. Please forgive my lack of knowledge for this is my first time doin this. I am still learning and thanks for your input.

InchUp

iTrader: (2)

If your heads will be off, measure it right then. Most factory engines will be in a range, but only measuring it will get an exact answer. From there you can order the correct head gasket.