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just like the title says. are there any reliability shortcomings of a 4.6 big bore as far short life expectancy due to heat or other issues. i plan on having the motor on the street. thanks, Dave
 

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No issues at all, everything works normally, especially if you go with one from Modular Performance. They were the first to be doing the process, but I've read some things about other engine builders out there who's product tends to eat head gaskets. It all has to do with the prep of the deck surface after the resleeve in an effort to have easier machining and lower costs. I don't know if John @ MP wants me letting out his trade secrets.

The only other issue is boost. Don't plan on running more than 16 PSI or so, since the head gaskets are so thin because of the fatter bores. But, then again, you'll make more power with less boost anyhow, so high pressure isn't really needed from the beginning.

Pete
 

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Oh, sorry about that. They are actualy Cometic head gaskets, really good pieces. If I recall correctly, typical materials don't survive because there is only 6mm of bore spacing between the cylinders after Modular Performance installs the new sleeves. The gaskets can even be reused once with no worries.

Pete
 

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I know that the company with the head gasket issue installs their 3.7" sleeves upside down compared to the way that Modular Performance or Renegade Racing do.

The only issue I have with my 5.0L Big-Bore is staying off the fun pedal.
 

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Yep, that and the way the sleeve and deck the block too....

Pete
 

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I also have a BB from Modular Performance. I could not be happier with my motor. It is VERY hard to stay off the pedal. Im running 9psi of boost right now, planning on going twin screw race kit from AED to 16psi soon. Im actually going to pulley for 16spi but will see about 14psi on the gauge due to my better flowing motor, so ill be more in the safe zone, but will be making great power. Im even going to top it off with about a 50-75hp shot for those close races.

If your going BB I would go with Modular Performance or Renagade.

Its also my daily driver.

Good luck.
 

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All depends on what cams you use and what heads you go with, especially when you choose between SOHC and DOHC. But, for a SOHC, plan on getting 40-60 more RWHP than an identical motor of the standard bore. The shape of the dyno curve stays almost identical, but how much you get depends on a lot of factors.

Pete
 

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Tim said:
How much horse does a 5.0 big bore have? just a question i'm thinking about getting one.
Mine made 294 RWHP uncorrected on a Mustang Dyno in 95+ weather and 100% humidity.
 

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TGJ said:
Mine made 294 RWHP uncorrected on a Mustang Dyno in 95+ weather and 100% humidity.
With what other mods?
 

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awdRocks said:
With what other mods?
Breakdown is this.

Renegade Racing Big-Bore, roughly 10.2:1 Compression ratio
Renegade Racing P&P NPI heads
Crower Stg 2 PI SC cams
Plastic PI intake
C&L upper intake
BBK 75mm TB
Big Kooks TBird headers
TFHS 4R70W
4200 RPM Stall TC
4.30 TLok Rear-end

There is a few other things if you want all the nitty gritty. You can read about that here. Due note, even though the numbers don't really reflect it, I am pretty sure SAE corrected on a DynoJet, the car would make around 330 RWHP as is.
 
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