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Discussion Starter #1
hey guys, prett new here to the forum and looking at a GM sportsman block P/N 12480157 for a very reasonable price. it's brand new, never been machined and am wondering if it will hold up to the power i'm hoping to make. its a 350 main w/ nodular iron 4 bolt splayed caps and 400 bore size. i have a rolled set of 18 degree brodix pontiac heads that flow right around 350 cfm's at .700" and am looking at 250-300hp worth of nitrous. looking to make 675hp on motor (w/ E85) and the extra 250-300 on the gun. think i have a shot at keeping it together? thanks for you're help.
 

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DamCoonass
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I would change the caps, pour it & run the snot out of it.
 

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Discussion Starter #3
yea man, was definitely considering a fill. i guess to change the caps i could probably get them from gm and have it line bored.
 

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if you are going to the expense of changing caps and fill a brand new block... just get a dart block. I think you will save money in the long run.
 

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if you are going to the expense of changing caps and fill a brand new block... just get a dart block. I think you will save money in the long run.
X3
 

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Those nodular caps willl take the Beating all day long @ that power level...........

make sure it's stud'ed..... and the rotator balanced right, and let it eat................

FWIW, you should be able to make 725++ with those heads on motor alone.......
 

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Those nodular caps willl take the Beating all day long @ that power level...........

make sure it's stud'ed..... and the rotator balanced right, and let it eat................

FWIW, you should be able to make 725++ with those heads on motor alone.......
X2
Before they had all the Billet caped blocks, the sportrman block was the choice block. I would run it!
 

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Discussion Starter #10
thnx for your help guys, i can get it for around $1400 so it's way cheaper than a lil m or motown. and as far as the heads for 725hp, that would be nice! keeping compression to around 12:1 so i figure 675 is a good conservative number with a single 4150 carb, but definitely agree that 725 is feasible. have some cash to blow on this thing, but trying to stay on somewhat of a budget.
 

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Dart SHP is 1446$ new? Whites performance and machine has them all machined and ready to assemble. 423-288-3881ph.
 

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Discussion Starter #12
Dart SHP is 1446$ new? Whites performance and machine has them all machined and ready to assemble. 423-288-3881ph.
yes, i have seen very good deals on the SHP blocks, but i'm under the impression that it's going to be at a marginal strength level making this kind of power? dart rates them for in the neighborhood of 700hp, which i should be over by 2-300hp. idk, maybe i'm just being a bit conservative, as i hear stories of these guys making 800+ on 4 bolt truck blocks, but then again maybe they're just stories after all?
:confused:
 

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Dart is very conservative on thier ratings. I'm sure there is people on here that make considerably more than 700, with thier SHP's.
 

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I think either one will work just fine. The Bowtie "might" have a better Bulkhead on their block. Maybe Carl or someone else will chime in. But either way, they both will work fine!
 

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Seeing that block is 1184 casting with the thick bulk heads its not a bad piece.

Dart rates there Sportsman block around 1200 horse it uses a 2 bolt front cap and 2 bolt rear cap with 1/2 hardware.

The Bowtie Sportsman block use 4 bolt caps from front to rear.

I would stud the mains down the center and run it as its better then the SHP block and I feel its as good as the Dart Sportsman block. Ya a better block would be the Dart with billet caps or the 2503 Bowtie.

On the Sportsman blocks I have seen its a good idea to dust out the mains as they are line bored and the finish looks like a mirror until its line honed and have seen this is issue on every sportsman block.

Here is a pic of Hordogs block as the main bearings did not look good and I dusted out the main line it shows the imperfections of the line bore. Just above the groove cut in the mains you can see the chatter marks.
 
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