DCR and my 408
04-04-2006, 11:23 PM
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DCR and my 408 Here's what I got so far.
The typical 408
4.030 x 4.00 w/ 6.125 rods
-2cc pistons which poke out .007 so I was told.
cam is 248/254 114 @ .050 and 301/306 @ .006
I'm thinking 12:1 CR right now, which would put me at about 8.1 on DCR. Can I get away with bumping the SCR up even more?
I don't have the heads yet, so I can change that part, the rest is a constant, and more than likely not changing. The cam would be the only other thing that CAN change, but probably won't.
What would I benefit from bumping compression, resulting in the increased DCR too?
This is going in a truck, will run 93octane gas, an see life as a truck (towing a jet ski or 2 and a 4 wheeler or 2, 1-3k pounds max) occasionally, but mostly as a DD.
The typical 408
4.030 x 4.00 w/ 6.125 rods
-2cc pistons which poke out .007 so I was told.
cam is 248/254 114 @ .050 and 301/306 @ .006
I'm thinking 12:1 CR right now, which would put me at about 8.1 on DCR. Can I get away with bumping the SCR up even more?
I don't have the heads yet, so I can change that part, the rest is a constant, and more than likely not changing. The cam would be the only other thing that CAN change, but probably won't.
What would I benefit from bumping compression, resulting in the increased DCR too?
This is going in a truck, will run 93octane gas, an see life as a truck (towing a jet ski or 2 and a 4 wheeler or 2, 1-3k pounds max) occasionally, but mostly as a DD.
200-250 MAX.
04-05-2006, 12:26 AM
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I would keep it where it is. DCR of around 8.8:1 or so is what I would consider max safe compression with 93 octane. If you're going to be towing, you should be just fine with that setup in a daily driver.
04-05-2006, 07:59 AM
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Yeah, I wouldn't go any higher than that. In the florida heat, I'm getting away with my 408/12:1 comp a max of 18-16* of timing depending on where I'm at in the power band.
It was still in the 50's 2 months ago, I was able to run 21/18* respectivley. My SCR is 12:1 and DCR is 8.3
Dougie
It was still in the 50's 2 months ago, I was able to run 21/18* respectivley. My SCR is 12:1 and DCR is 8.3
Dougie
