They always say you should have a plan... I need help with mine
11-08-2006, 09:33 AM
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They always say you should have a plan... I need help with mine Hey guys,
As some of you may know, I pulled my motor last night and am planning on a rebuild. I'm trying to decide a couple things about the rebuild and what parts to use. Here is my long-term plan:
1) Rebuild the motor.
2) Run N/A.
3) Get a D-1SC or F1.
4) Get a 408 built for the Procharger.
5) Kick ***.
Now, I'm considering rebuilding the engine in its stock form, running N/A, then getting some 6.0L heads to lower the compression ratio when I get the Procharger. Then I'll build the 408 for the Procharger with a lower compression ratio (8.5:1) and forged internals.
However, I'm thinking that I could put off the 408 for a longer period of time if I could make this engine a little more boost friendly. I'm considering forged rods and pistons. If I get them, I'm thinking that I might get low compression pistons with valve reliefs so that I can mill the stock heads and keep the compression ratio relatively close to stock. Then, when I get the 6.0L heads (which won't be milled) I'll be able to lower the compression ratio more than I would have with the stock internals.
Does the second plan sound like a viable one? How much could I mill the stock heads if I were to do this? Where would this put my CR? How low could I get the CR after slapping the 6.0L heads on? Any other input?
TIA, everyone.
As some of you may know, I pulled my motor last night and am planning on a rebuild. I'm trying to decide a couple things about the rebuild and what parts to use. Here is my long-term plan:
1) Rebuild the motor.
2) Run N/A.
3) Get a D-1SC or F1.
4) Get a 408 built for the Procharger.
5) Kick ***.
Now, I'm considering rebuilding the engine in its stock form, running N/A, then getting some 6.0L heads to lower the compression ratio when I get the Procharger. Then I'll build the 408 for the Procharger with a lower compression ratio (8.5:1) and forged internals.
However, I'm thinking that I could put off the 408 for a longer period of time if I could make this engine a little more boost friendly. I'm considering forged rods and pistons. If I get them, I'm thinking that I might get low compression pistons with valve reliefs so that I can mill the stock heads and keep the compression ratio relatively close to stock. Then, when I get the 6.0L heads (which won't be milled) I'll be able to lower the compression ratio more than I would have with the stock internals.
Does the second plan sound like a viable one? How much could I mill the stock heads if I were to do this? Where would this put my CR? How low could I get the CR after slapping the 6.0L heads on? Any other input?
TIA, everyone.
11-08-2006, 10:46 AM
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I don't know the cc's of any of the stock parts. But I put some typical numbers in the calculator, in part because I've considered a similar plan myself. These examples all assume zero deck height. Quench may be too fat that way.
With 59cc heads, a 12cc dish, and .040 gaskets, you get 9.98:1, not great but liveable for NA.
With 72cc heads, a 12cc dish, and .054 gaskets, you get 8.49:1.
If your low-compression heads were 76cc, and you could get 8cc pistons, you could run these two packages:
59 cc heads, 8cc dish, .040 gaskets: 10.47:1, better.
76cc heads, 8cc dish, .054 gaskets, 8.49:1
So it looks like this is probably doable, but you'll probably have to lean it one way or the other. There isn't quite enough stretch in the head cc values to make both setups ideal. You'd want to run all the numbers yourself for both setups to make sure you don't paint yourself into a corner.
With 59cc heads, a 12cc dish, and .040 gaskets, you get 9.98:1, not great but liveable for NA.
With 72cc heads, a 12cc dish, and .054 gaskets, you get 8.49:1.
If your low-compression heads were 76cc, and you could get 8cc pistons, you could run these two packages:
59 cc heads, 8cc dish, .040 gaskets: 10.47:1, better.
76cc heads, 8cc dish, .054 gaskets, 8.49:1
So it looks like this is probably doable, but you'll probably have to lean it one way or the other. There isn't quite enough stretch in the head cc values to make both setups ideal. You'd want to run all the numbers yourself for both setups to make sure you don't paint yourself into a corner.
11-08-2006, 12:31 PM
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Okay. Can anyone give me the following info?
1) Combustion chamber size of stock LS1 heads.
2) Combustion chamber size of 6.0L heads (I'm assuming these are LS2 heads?)
3) Combustion chamber size of stock LS1 head milled 0.030" (can you mill any more than that?)
4) What is the quench on a stock engine?
1) Combustion chamber size of stock LS1 heads.
2) Combustion chamber size of 6.0L heads (I'm assuming these are LS2 heads?)
3) Combustion chamber size of stock LS1 head milled 0.030" (can you mill any more than that?)
4) What is the quench on a stock engine?
11-08-2006, 03:42 PM
#4
Due to the cost of big cubes and FI, I've observed that most of these plans never come to pass and people wind up with a half-assed combo. If you are going to build FI, you can make plenty of power on stock cubes. Rebuild your motor for FI and skip the 408. Otherwise I'd build a 408 for NA. You could always throw a 100 - 150 shot on top if you get bored later.
