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FFCobra Fanatic
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7,022 Posts
Discussion Starter · #1 ·
I am running a 87 stock 302.
I don't think it will last long running 8-10 pounds of boost and close to 400RWHP.
I was looking at the Ford motor sport catalog at the Sportsman block and the boss block. They rate the Sportsman block for around 450HP? Nothing on the Boss.

I looked on line at a DSS stage (stock blocks) 10 and 20 block.
How can they rate them 650+HP? With main cap support. What do you guys think? I want 500FWHP with boost.

john
 

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Senior Charter Member
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3,086 Posts
About 500rwhp seems to be the rule of thumb on the stock block. Some come apart earlier (450rwhp), others seem to last forever.

Of course depends on the source of info, but some feel the support girdle isn't really effective.
 

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Banned
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551 Posts
Mine was fine at 513 rwhp. Many track runs besides all of the street driving.

Put a smaller pulley on it and it lasted four good runs at the track then broke : )

Narve is absolutely right, some last longer some break sooner.

You will need to put in stronger internals at that power level though (crank, rods, pistons).

The new Boss block is supposed to be very strong like the R block but with better cooling. That'll be my next block when I break my second one.

Tom
 

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340 Posts
I believe at around 700ish hp the block splits in half right down the lifter valey. Read it in a 5.0 magazine where they were experimenting on how much the stock block would take before exploding. They kept adding boost until failure. It actually lasted a few runs before it let go. Pretty impressive for a block rated at 225 hp from the factory.
 

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Junior Charter Member
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252 Posts
At 400rwhp less than 5% of factory blocks will fail. At 500rwhp it's probably closer to 20%.

The factory crank, rods and pistons are stronger than the block itself. You don't need to upgrade anything in the shortblock until you go to a stronger block.
 

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Former Roadster Owner
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1,861 Posts
I think that anything pass 450rwhp could be considered risky. I'm pusing a hair over 400rwhp and I'm not planning on a failure.


-dan
 
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