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  #16 (permalink)  
Old 07-24-2013, 08:35 PM
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Oh wow, those cheap scat 9000 cranks are pretty solid. Im going to look into a kit with one if I can sell what I have. Will the 432 rotating assembly work for what I have though? All I have so far is the rotating assembly block and heads
It will go in a 2wd shortbed chevy street/strip
454 block .030" over
427 crank making 432"
781 heads 2.19/1.88 118cc chamber
Hydraulic roller cam im thinking something in the .600" lift range to take advantage of the head flow
Dual plane intake
th400 that will be built and whatever recommended stall converter
Rear gears will be decided at the same time
The main issue i see is very low compression, 9.07:1 with the 16.5cc pistons I have. I dont think that would make a good combo. I wanna make around 550hp for whatever thats worth

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Old 07-24-2013, 08:44 PM
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I'm purdy sure thats a 3904815. Makes it a 396,402...cast, nodular iron according to Mortec and others. Look closely at the other "8" and see the difference in the center of the digits. The "8" is straight across where the "9" is slightly slanted.

As far as 'ringing' a crank to tell if it's forged or cast, unless you have a hell of an ear for it- as in you handle cranks daily- you can't tell cast from forged. If you have two similar cranks, one forged and one cast, they'll sound different but unless you know which is which and ring them at the same time, all you'll know is they ring differently.

Last edited by cobalt327; 07-24-2013 at 08:53 PM.
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  #18 (permalink)  
Old 07-24-2013, 08:47 PM
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aww man why do you have to ruin my fun. I'll check it out when im home friday. Good eye but im praying youre wrong
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Old 07-24-2013, 09:02 PM
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I hope I'm wong too! The number can go either way, depending on what you want to see:



The parting line will be the easiest to see indicator:



Good luck!!
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Old 07-25-2013, 09:18 AM
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Quote:
Originally Posted by 1986c10 View Post
Oh wow, those cheap scat 9000 cranks are pretty solid. Im going to look into a kit with one if I can sell what I have. Will the 432 rotating assembly work for what I have though? All I have so far is the rotating assembly block and heads
It will go in a 2wd shortbed chevy street/strip
454 block .030" over
427 crank making 432"
781 heads 2.19/1.88 118cc chamber
Hydraulic roller cam im thinking something in the .600" lift range to take advantage of the head flow
Dual plane intake
th400 that will be built and whatever recommended stall converter
Rear gears will be decided at the same time
The main issue i see is very low compression, 9.07:1 with the 16.5cc pistons I have. I dont think that would make a good combo. I wanna make around 550hp for whatever thats worth
Using Summit's Compression calculator with your numbers...
4.280 bore (4.25 +.030)
3.76 stroke
118 cc heads
-16.5 cc domed pistons
assumed .020 piston-to-deck clearance
assumed Felpro gasket with 4.370 bore and .039 compressed thickness
I get 8.69:1 CR and 432.77 CID

Using Wheelspin's calculator
I get 8.65:1

I've just removed my 781 heads and replaced them with 063 versions (68/69 396 closed 101cc chambers) hoping to get around 9.0:1 with my flat-tops.

Your setup with 063 heads would be awfully close to 10:1 ... which is right where you probably want to be.

From what I have read in regards to quench, decking the block to 0.00 would give you good quench and an additional .4 (10.4:1) compression. I also think, again based on what I have read, that the "perfect" CR is 10.25:1

I would also point out that you're obviously giving up some cubes with that shorter stroke. Is there a reason that you want or need to do this?
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  #21 (permalink)  
Old 07-25-2013, 02:16 PM
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I think why you got that low was because of your deck and compressed gasket thickness values. I used values of .02 and .02ish i think to achieve around a .040" quench. Giving a little over 9:1. I got this assembly in a trade and would much rather go with a 4.25 stroker kit and am leaning that way alot more with the little compression this engine has. I feel like i would have to run a smaller cam etc with that low of comp. And thats a good thought about the heads but I just had them rebuilt and have way to much $ into them to get rid of them haha.
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